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2010-02-14 07:14:48
asvab general science

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  1. classification of animale and plant kingdom
  2. Homo sapiens: scientific name for man
    • Escherichia coli: scientific name of the microorganism that inhabits the intestines of man
    • The classification system has 7 levels. The top level contains the largest number of different
    • kinds of organisms and is called the kingdom. The bottom level with the smallest number of
    • different kinds of organisms is called the species. The levels are:
    • 1. KINGDOM—contains several related phyla
    • 2. PHYLUM—contains several related classes
    • 3. CLASS—contains several related orders
    • 4. ORDER—contains several related families
    • 5. FAMILY—contains several related genera
    • 6. GENUS—contains several related species
    • 7. SPECIES—contains all organisms with the same characteristics
    • Scientists have struggled to find the best method of grouping organisms for hundreds of years.
  3. The most accepted theory is the five-kingdom system. This includes:
  4. • Animals
    • • Monerans
    • • Protists
    • • Fungi
    • • Plants
  5. Monerans and Viruses
  6. Monerans are simple one-celled microscopic organisms. They lack internal structures within
    • their cells and have a simple circular molecule of DNA instead of a nucleus. This kingdom includes
    • bacteria and blue-green algae. Many bacteria are known as parasites, which cause diseases
    • (tetanus, gonorrhea, and strep throat), or as decomposers, which absorb food from decaying
    • materials or living things. Blue-green algae make their own food by photosynthesizing.
    • Viruses are a type of life that scientists have difficulty in defining. They do not fit easily into any
    • classification scheme because they do not have a true cell structure. Some scientists describe
    • them as nonliving things, even though they contain protein and nucleic acid. Many human diseases
    • are caused by viruses (polio, influenza, AIDS, herpes, measles, etc.). Viruses cause diseases by
    • using another cell’s material to reproduce.
    • Protists
    • Protists are microscopic one-celled organisms that have a true nucleus, as well as many other
    • structures found in more complex cells. Protists differ from each other in the way they obtain
    • food. Some depend on other organisms for food, and some can photosynthesize. This kingdom
    • includes protozoa, one-celled algae, and slime molds.
    • Fungi
    • Fungi are many-celled organisms with complex cell structure. Their cells lack chloroplasts that
    • are necessary in photosynthesizing. They are decomposers. This kingdom includes bread molds,
    • mushrooms, and yeasts.
  7. The Plant Kingdom
  8. The two principal plant phyla are the Bryophyta and Tracheophyta. Bryophytes do not have a
    • vascular system for transporting water, food, and minerals; tracheophytes do have a vascular
    • system.
  9. Phylum Bryophyta
  10. Bryophytes are nonvascular plants and have no true roots, stems, or leaves. Because they lack
    • woody tissue, they generally grow only a few inches in height. Common types of bryophytes are
    • mosses, many-celled algae, and liverworts.
  11. Phylum Tracheophyta
  12. Tracheophytes are vascular plants and have true roots, stems, and leaves. The three principal
    • classes are:
    • 1. Class Filicineae—Ferns do not produce flowers or seeds. However, spore-producing
    • generations of plants do occur in their life cycles. They require moist, shady areas.
    • 2. Class Angiospermae—Angiosperms are flowering plants that produce seeds with
    • protective coverings. The seed and protective tissue are called fruit. Angiosperms are
    • divided into monocots and dicots.
    • Monocots have seeds with only one cotyledon, a food-bearing structure. They have
    • long, narrow leaves and parallel veining. The flowering parts are arranged in threes or
    • multiples of three (banana, corn, and wheat).
    • Dicots have seeds with two cotyledons. They have broad leaves and branched veining.
    • The flowering parts are arranged in fours or fives or multiples of four or five (apple and
    • maple).
    • 3. Class Gymnospermae—Gymnosperms produce seed without any protective coverings.
    • Conifers, such as cedar, fir, pine, and spruce, are evergreens that produce seed
    • cones.
  13. The animal kingdom can be divided into two groups
  14. 1. Invertebrates—those that do not have a backbone
    2. Vertebrates—those that have a backbone
  15. Invertebrates
  16. Phylum Porifera the simplest animals; also called sponges;
    • mostly marine animals that feed on microscopic
    • organisms; porous and lack bony skeletons or tissues.
    • Example: sponge
    • Phylum Coelenterata more complex organisms having simple tissues;
    • marine animals
    • Examples: coral; jellyfish; sea anemone
    • Phylum Platyhelminthes flatworms are the simplest animals with bilateral symmetry
    • and organs; often live as parasites in humans; flat body
    • Examples: tapeworm; liver fluke
    • Phylum Nematoda roundworms have a digestive tract with two openings;
    • most are parasitic
    • Examples: ascaris; hookworm; trichina
    • Phylum Annelida long, segmented, cylindrical bodies; the only parasitic
    • annelid is the leech
    • Examples: earthworm; leech
    • Phylum Mollusca soft bodies enclosed in a mantle; move by means of a
    • muscular foot; three principle classes:
    • Univalves—single-coil shell
    • Example: snail
    • Bivalves—two shells connected by a hinge
    • Examples: clam; mussel; oyster; scallop
    • Head-foot—no shell
    • Examples: squid; octopus
    • Phylum Echinodermata aquatic animals with spiny skins; some have five or more
    • arms that spread out in radial symmetry
    • Examples: starfish; sea urchin; sea cucumber
    • Phylum Arthropoda contains the largest number of animals; segmented bodies
    • covered by an external skeleton; jointed appendages;
    • generally have three distinct body regions (head, thorax, and
    • abdomen)
    • Examples: lobster; shrimp;
  17. The major classes of anthropoda and their characteristics are:
  18. Crustaceans: have five or more pairs of jointed legs and gills for respiration. The
    • lobster, shrimp, and crab are common crustaceans.
    • Myriapods: include the centipede and millipede. They have long bodies made up of
    • numerous segments with legs on each segment. The centipede has one pair of legs per
    • segment; the millipede has two pairs on each segment.
    • Arachnids: have two body regions and four pairs of legs. The spider and scorpion are
    • in this class.
    • Insects: comprise the largest group of arthropods. Insects have three pairs of legs and
    • generally one or two pairs of wings. The ant, bee, butterfly, fly, grasshopper, locust,
    • louse, mosquito, and moth are common insects.
  19. Vertebrates
  20. Fish cold-blooded; use internal gills for respiration; use fins for
    • locomotion
    • Examples: bass; trout; perch; mackerel; shark; etc.
    • Amphibians can live both in the water and on land; cold-blooded;
    • develop lungs in the adult stage
    • Examples: frog; toad; salamander
    • Reptiles cold-blooded; breathe air through lungs; have legs for movement
    • (except snakes); most lay eggs with tough shells
    • Examples: alligator; crocodile; lizard; snake; turtle
    • Birds warm-blooded with feathers and wings; lay eggs with
    • brittle shells; there are many different kinds of birds with
    • some raised for human consumption
    • Examples: chicken; goose; turkey
    • Mammals warm-blooded with hair or fur on bodies; breathe by means
    • of lungs; newborns are fed milk from the mother’s
    • mammary glands; mammals are divided into many orders
    • based on differences in body structure
    • Examples: duckbill platypus; kangaroo; beaver; mouse; rat;
    • squirrel; dolphin; porpoise; whale; cat; dog; fox; lion; wolf;
    • cow; deer; horse; pig; sheep; ape; human; monkey
  21. The major classes of mammals and their characteristics are:
  22. Monotremes: the most primitive mammals, lay eggs (duckbill platypus)
    • Marsupials: carry their young in the pouch on the mother’s body (kangaroo)
    • Rodents: gnawing mammals (beaver, mouse, rat, and squirrel)
    • Cetaceans: marine mammals with forelimbs that have been modified to flippers (dolphin,
    • porpoise, and whale)
    • Carnivores: have sharp claws and powerful jaws (cat, dog, fox, lion, and wolf)
    • Ungulates: hoofed mammals with teeth adapted for grinding (cow, deer, horse, pig, and
    • sheep)
    • Primates: possess a highly developed brain, stand erect, and have the ability to grasp
    • and hold objects with their two hands (ape, human, and monkey)
  23. Humans are part of the primate order. They are unique in their species in that they have characteristics
    that set them apart from other primates. These characteristics include:
  24. • Power of speech
    • • Bipedalism, or the ability to walk on two legs instead of four
    • • Adaptability to almost any environment
    • • Ability to remember
    • • Ability to make associations between ideas
  25. Major Systems of the Human Body
  26. The human body is a complex machine that operates in a most effective and precise manner. It
    consists of several major systems that work together with extreme efficiency.
  27. The human skeleton is the supporting framework of the body. It consists of more than 200 bones
    connected by joints (see Figure 2). The four main types of joints are:
  28. 1. Fixed joints, as in the skull, hold the bones firmly together.
    • 2. Hinge joints, as in the knee and finger, are partly movable and provide some
    • Flexibility.
    • 3. Pivot joints, as in the elbow, are similar to hinge joints but can also be rotated.
    • 4. Ball and socket joints, as in the hip or shoulder, provide greatest flexibility.
    • The surfaces of joints are lined and cushioned by a flexible material called cartilage. Cartilage is
    • also found in the outer ear and the tip of the nose. Bands of tissue called ligaments support the
    • bones of movable joints.
  29. The Muscular System
  30. This system enables the body to move. The body has more than 600 skeletal muscles that are
    • made up of bundles of striated (or voluntary) muscle fibers. Each end of the muscle is attached to
    • the bone by connective tissue called tendon. Movement results from the contraction of these
    • muscles that always operate in pairs. For example, the contraction of the biceps while the triceps
    • are relaxed causes the elbow to bend; the contraction of the triceps while the biceps are relaxed
    • causes the elbow to straighten (see Figure 3 on page 104). The skeletal muscles are known as
    • voluntary muscles because they are controlled by the individual through conscious thought.
  31. The Digestive System
  32. The digestive tract is essentially a long, winding tunnel that extends from the mouth to the anus. It
    includes the mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus
  33. The digestive system controls food intake, digestion, and the absorption of the digested material
    by the body cells for energy and bodybuilding. The six important steps in digestion are as follow
  34. 1. Mouth: The teeth and tongue aid in mechanical digestion. Amylase contained in the
    • saliva acts on the starch.
    • 2. Stomach: Food is mixed with acidic gastric juice and pepsin, which acts on the protein.
    • 3. Small intestine: The bulk of digestion occurs in the small intestine. The food pulp mixes
    • with alkali and digestive juices that are manufactured by the pancreas and the liver and
    • released into the duodenum, the beginning of the small intestine. The juice manufactured
    • by the pancreas contains lipase, which changes fat to glycerol and fatty acids; amylase,
    • which changes complex carbohydrates to simple sugars; and trypsins, which change
    • polypeptides to amino acids. Bile produced by the liver and stored in the gallbladder aids
    • in the digestion and absorption of fats and oils.
    • Absorption of all digested substances, except the fatty acids and glycerol, occurs in the
    • small intestine through capillaries that carry the blood to the liver and then to all body
    • cells. Fatty acids and glycerol are absorbed and transported by the lymphatic system to
    • the neck before entering the bloodstream.
    • 4. Large intestine: The large intestine produces certain vitamins and is responsible for the
    • absorption of those vitamins, water, and essential minerals from the remaining material.
    • 5. Rectum: The rectum stores the solid waste.
    • 6. Anus: The anus releases the solid waste from the body periodically. The kidneys return
    • needed water and minerals to the blood but send the liquid waste (urine) to the bladder,
  35. The Nervous System
  36. The nervous system includes the brain, spinal cord, and the network of nerves. It receives and
    • responds to all stimuli (see Figure 5 below). The brain, protected within the skull, consists of two
    • cerebral hemispheres, the cerebellum and the brain stem or medulla oblongata
  37. The main components of the nervous systems and their functions are:
  38. • Cerebrum or forebrain: major part of the brain and is responsible for many human
    • abilities, such as hearing, seeing, speaking, learning, etc.
    • • Cerebellum: concerned with muscular coordination and is responsible for the
    • coordination of impulses sent out from the cerebrum. It also controls posture and
    • balance.
    • • Brain stem: connects the brain with the spinal cord. It controls several involuntary
    • activities, such as heartbeat rate and breathing rate.
    • • Spinal cord: major connecting center between the brain and the network of nerves.
    • It is also the control center for many simple reflexes.
  39. The Endocrine System
  40. The endocrine system is a group of specialized organs and body tissues that produce, store, and
    • secrete chemical substances. These chemical substances are known as hormones and are chemical
    • regulators that control growth, metabolism, and reproduction. They are produced by endocrine
    • glands and the brain controls their release into the bloodstream. When they are released, specific
    • hormones affect specific tissues and processes in the body
  41. The principal endocrine glands and some of their functions are explained in the following chart.
    • Pituitary 1. Growth hormone 1. Growth of muscle, bone, and other
    • connective tissue
    • 2. Vasopressin 2. Increases blood pressure; increases
    • reabsorption of water into blood from
    • kidneys
    • Thyroid Thyroxin Energy release process in the cells
    • Parathyroid PTH (parathyroid Nerve impulses and muscle contraction,
    • hormone) strength of bones
    • Pancreas 1. Insulin 1. Regulates the amount of sugar in the blood;
    • speeds up the storage of excess sugar
    • 2. Glucagon 2. Speeds up the removal of stored sugar
    • Adrenal glands Adrenaline Readies the body for strenuous physical
    • activity; increases the amount of sugar in the
    • blood
    • Testes Androgens Controls development of sex characteristics
    • of adult males
    • Ovaries Estrogens Controls development of sex characteristics
    • of adult females
  43. Endocrine organs have no ducts connecting them to specific body parts. The main functions of
    endocrine glands include:
  44. • Body’s growth and development
    • • Control of the function of various tissues
    • • Support of pregnancy and other reproductive functions
    • • Regulation of metabolism
  45. The Circulatory System
  46. The circulatory system’s main organ is the heart. It pumps oxygenated blood at high pressure to
    • every part of the body through arteries and capillaries, back to the heart at reduced pressure
    • through small veins and large veins, back to the lungs for oxygenation, and then back to the heart
    • to repeat the cycle.
    • The heart is a pear-shaped organ that lies in the center of the chest. The lungs are shaped like
    • elongated ovoids and lie on either side of the heart. The heart has four chambers—the right
    • atrium, the left atrium, the right ventricle, and the left ventricle
  47. The nine principal steps in the circulation of blood are as follows:
  48. 1. Blood from the body enters the right atrium of the heart.
    • 2. Contraction forces the blood into the right ventricle.
    • 3. Contraction forces the blood into the pulmonary artery, which goes to the lungs.
    • 4. In the lungs, oxygen is picked up and carbon dioxide is removed from the
    • blood.
    • 5. Oxygenated blood from the lungs travels through the pulmonary veins to the left atrium.
    • 6. Contraction forces the oxygenated blood into the left ventricle.
    • 7. Strong contraction of the left ventricle forces oxygenated blood into the aorta.
    • 8. Arteries and capillaries carry the oxygenated blood to all blood cells.
    • 9. Blood returns through small veins and then large veins back to the right atrium of
    • the heart.
    • Chapter 4: Strengthening Your Weaknesses
    • 1. Blood from the body enters the right atrium of the heart.
    • 2. Contraction forces the blood into the right ventricle.
    • 3. Contraction forces the blood into the pulmonary artery, which goes to the lungs.
    • 4. In the lungs, oxygen is picked up and carbon dioxide is removed from the
    • blood.
    • 5. Oxygenated blood from the lungs travels through the pulmonary veins to the left atrium.
    • 6. Contraction forces the oxygenated blood into the left ventricle.
    • 7. Strong contraction of the left ventricle forces oxygenated blood into the aorta.
    • 8. Arteries and capillaries carry the oxygenated blood to all blood cells.
    • 9. Blood returns through small veins and then large veins back to the right atrium of
    • the heart.
    • Figure 8. The circulation of blood through the heart
    • The heartbeat reflects the contraction of the heart. The normal adult heartbeat is 72 beats per
    • minute. The pulse rate and the heartbeat rate are the same. Each heartbeat consists of two
    • stages. The powerful muscular contraction of the ventricles is the systolic stage, when blood is
    • pumped into the aorta. The other stage is the diastolic, or rest stage. Blood pressure is the ratio
    • of systolic over diastolic pressure measured in millimeters of mercury. Normal adult blood pressure
    • is approximately 120/80.
  49. The four principal components of blood are
  50. 1. Red blood cells (erythrocytes): carry oxygen and carbon dioxide
    • 2. White blood cells (leukocytes): produce antibodies and fight off infections
    • 3. Platelets: cell fragments involved in blood clotting
    • 4. Proteins: involved in blood clotting and antibody production
  51. The Respiratory System
  52. The respiratory system’s main function is to breathe air into and out of the lungs, oxygenating the
    • blood while eliminating carbon dioxide. Oxygen diffuses into the blood, while carbon dioxide moves
    • out of the blood via the lungs and out of the body via the mouth or nose. Using oxygen to oxidize
    • the intracellular nutrients releases energy into the body. Exhalation of air rids the body of carbon
    • dioxide, a waste product of oxidation.
  53. The respiratory system consists of the following
  54. • Nose and nasal cavity—filter, moisten, and warm inhaled air
    • • Throat—aids in protection against infection
    • • Windpipe—provides a passageway for the air
    • • Bronchi—two tubes that connect the windpipe with the lungs
    • • Lungs—capillary vessels of the lungs exchange gases between the air and
    • the blood
    • • Blood—the oxygen combines with the hemoglobin in the red blood cells and is carried
    • throughout the body to the cells. Carbon dioxide is carried back to the lungs where
    • this waste product is exchanged for oxygen.
  55. Lymphatic System
  56. The lymphatic system filters impurities out of the fluid that surrounds body tissues and comprises
    • a network of organs, ducts, and tissues. The organs are divided into two categories:
    • 1. The primary lymphatic organs. These consist of the thymus and bone marrow, which
    • produce lymphocytes. Although the thymus is critical for T-cell development in children,
    • it begins to shrink as they progress toward adulthood.
    • 2. The secondary lymphatic organs. These include the spleen, appendix, tonsils, adenoids,
    • lymph nodes, and Peyer’s patches in the small intestine. Tonsils reach full size at
    • approximately age 7, then gradually shrink until adulthood. Tonsils and adenoids were
    • routinely removed surgically in the past in most children. Today, tonsils are not removed
    • unless a child experiences repeated infections of the tonsils, known as tonsillitis.
    • Lymph nodes are mainly clustered in the pelvic area, the neck, and the armpits. They are the
    • lymphatic system’s way to fight infection and are connected to each other by lymphatic vessels.
    • White blood cells in the nodes and other secondary organs surround and destroy debris to prevent
    • it from reentering the bloodstream.
  57. The Excretory System
  58. The excretory system involves several organs, including some involved in digestion and respiration,
    • and is responsible for the removal of waste substances from the body. The main organs of the
    • excretory system are:
    • • Skin: excretes waste through perspiration
    • • Large intestine: absorbs water from solid food waste, stores and eliminates waste
    • • Kidneys: filter blood and excrete waste in the form of urea
    • • Liver: excretes bilirubin
    • • Lungs: excrete carbon dioxide
  59. The Reproductive System
  60. Humans reproduce by the union of a male sperm and a female ovum. The male organ ejaculates
    • more than 250 million sperm into the vagina, from which some make their way to the uterus and
    • the fallopian tubes that provide passage from the ovaries to the uterus. Ovulation, the release of an
    • egg into a fallopian tube, occurs approximately every 28 days; meanwhile the uterus is prepared
    • from the implantation of a fertilized ovum by the action of estrogen. If sperm unites with an ovum,
    • a zygote is formed that eventually develops into a fetus. If no sperm unites with the ovum, other
    • hormones cause the uterine wall to slough off during menstruation. From puberty to menopause,
    • the process of ovulation, preparation, and menstruation is repeated monthly except for periods of
    • pregnancy. The duration of pregnancy is approximately 280 days. After childbirth, prolactin, a
    • hormone secreted by the pituitary, activates the production of milk.
  61. Health and Nutrition
  62. Humans obtain energy from food for maintenance, growth, and repair. A healthy diet contains
    • sufficient quantities of macronutrients, such as proteins, carbohydrates, and fats, because they
    • are energy producers.
    • Proteins are necessary for the growth and repair of body tissues. Animal proteins are contained
    • in meat, fish, eggs, and cheese. Vegetable proteins are found in peas, beans, and other legumes as
    • well as in grains.
    • Carbohydrates comprise the starches and sugars. Starches are found in bread, cereals, pasta,
    • vegetables such as potatoes, and rice. Sugars are obtained from fruits, cane sugar, and beets.
    • Cakes and pies contain excessive amounts of sugar and should be eaten sparingly.
    • Fats may be of plant or animal origin. Although some fat is needed for body growth and repair,
    • excess fat is retained in the body as fatty tissue that can cause health problems.
    • Micronutrients, consisting of vitamins and minerals, are needed in smaller quantities because
    • they do not contain calories but are essential for health.
  63. Vitamins are required by the body to function well. Some of the more important vitamins are
    listed in the following chart.
  64. A Yellow and green leafy vegetables, Night blindness, rough
    • eggs, butter, meat and dry skin
    • B1 Whole grain cereals, liver, beef, peas, Beriberi with loss of
    • beans, pork, nuts appetite, nervous disorders
    • B2 Milk, leafy green vegetables, liver, Skin infections, general
    • enriched and fortified grain cereals weakness
    • B12 Meat, eggs, dairy products Pernicious anemia
    • C Citrus fruits, strawberries, tomatoes, Scurvy
    • green peppers, broccoli
    • D Milk, eggs, fish oil Rickets
    • E Green leafy vegetables, wheat germ, Sterility, hemolytic anemia
    • margarine, nuts
    • K Green leafy vegetables, eggs, dairy Slow blood clotting
  65. what are minerals?
  66. Minerals are needed in small quantities for proper metabolic functioning. Mineral salts are
    • chemical compounds containing sodium, calcium, phosphorus, potassium, magnesium, iron, chlorine,
    • fluorine, and iodine.
    • Fibers are needed for a healthy diet since they provide bulk, which enables the large intestine to
    • carry away body wastes. Water is also essential. The body loses approximately four pints of
    • water a day, which must be replaced. Since most foods contain water, replenishment generally
    • occurs.
  67. A balanced diet requires moderate eating of a variety of foods. Some foods are needed each
    day from each of the following four major groups:
  68. 1. Milk and Dairy Products. These foods provide the body with energy, protein, vitamins,
    • and minerals.
    • 2. Breads, Cereals, Rice, Potatoes, and Pastas. These foods provide energy for the body.
    • 3. Fruits and Vegetables. Both raw and cooked fruits and vegetables provide the body
    • with energy, minerals, vitamins, and roughage.
    • 4. Meats, Poultry, and Fish. These foods or substitutes, such as eggs, nuts, peas, and
    • beans, supply the body with energy, minerals, vitamins, and proteins.
  69. Human genetics is the study of heredity, the mechanism by which characteristics are passed from
    parents to offspring. Three basic laws of heredity were developed by Gregor Mendel in the late
    eighteenth century. These are:
  70. 1. The Law of Segregation: Individual heredity traits separate in the reproductive cells.
    • 2. The Law of Independent Assortment: Each trait is inherited independently of other
    • traits.
    • 3. The Law of Dominance: When certain contrasting traits are crossed, one trait will be
    • dominant and the other will be recessive.
    • Every child develops from a fertilized egg (zygote) that contains 23 pairs of chromosomes, or a
    • total of 46. Each pair consists of one chromosome from the mother and one from the father (see
    • Figure 10 on page 114). Each chromosome contains large numbers of hereditary units called
    • genes that determine physical and mental characteristics of the offspring. A gene is a unit of a
    • DNA molecule that carries a code for the production of a specific protein.
    • Meiosis is a specialized process of cell division in which gametes, also known as sex cells, are
    • produced by sexually mature adults. These gametes are in the haploid stage, they have only one of
    • each pair, or half the number, of chromosomes. The 23 pairs of chromosomes split into two sets of
    • 23 each. The chromosomes in the nucleus of each gamete are reduced from 46 to 23. At fertilization,
    • the 23 chromosomes from one parent combine with the 23 chromosomes from the other
    • parent to form a new cell with a total of 46 chromosomes. Sexual reproduction by meiosis and
    • fertilization results in great variation among offspring
  71. Sex Determination
  72. The sex of babies is determined by genes located on the pair of sex chromosomes. In the human
    • female, the two sex chromosomes are alike and are designated as XX. In the male, the sex
    • chromosomes are not alike and are designated as XY.
    • At fertilization, the zygote or fertilized egg receives an X chromosome from the mother but may
    • receive either an X or Y chromosome from the father (see Figure 10 below). If the paired chromosomes
    • are XX, the offspring will be female. If the paired chromosomes are XY, the offspring
    • will be male.
  73. Dominant and Recessive Characteristics
  74. Each person has two genes for each particular characteristic. These genes may be alike or not
    • alike. If the genes are alike, that person is homozygous for that characteristic. If the genes are not
    • alike, the person is heterozygous for that characteristic.
    • There are many common inherited characteristics and traits of people such as: hair color,
    • eye color, nose size and shape, earlobe shape, color vision, and blood type.
    • A person’s earlobe shape is determined by the gene received from each parent. To illustrate
    • this, the free earlobe is designated with a capital E in Figure 11 (page 115) because it is dominant,
    • and the attached earlobe with a small letter e because it is recessive. Consider the following:
    • • If the genes are alike and the person is homozygous for free earlobes designated by
    • EE, the individual will show free earlobes.
    • • If the genes are alike and the person is homozygous for attached earlobes designated
    • by ee, the individual will show attached earlobes.
    • • If the person received an E gene from one parent and an e gene from the other, the
    • person would be heterozygous for ear shape designated by Ee, but would show free
    • earlobes, the dominant form.
    • • If both parents have a genetic makeup of EE, the offspring will have a genetic
    • makeup of EE and will show free earlobes.
    • • If both parents have a genetic makeup of ee, the offspring will have a genetic makeup
    • of ee and will show attached earlobes.
  75. Ecology
  76. Ecology is the study of the relationship between organisms and their living and physical surroundings.
    • Every plant and animal is a member of a complex system called an ecosystem. In all ecosystems,
    • the following exist as interacting forces:
    • Producers (green plants): They make their own food via the photosynthesis process.
    • Consumers (animals): There are three types of consumers:
    • • Primary consumers, also known as herbivores, eat plants. Samples include grasshoppers,
    • rabbits, and cows.
    • • Secondary consumers, also called carnivores, are flesh-eaters. These include wolves,
    • snakes, and lions.
    • • Tertiary consumers include carnivores in their diet. Tertiary consumers may be
    • omnivores, corganisms that consume producers and consumers. Humans are omnivores
    • as a species.
    • Scavengers: This category feeds on dead organic matter. A vulture is an example of a scavenger.
    • Decomposers (bacteria and fungi): They break down dead organic matter and release minerals
    • back into the soil.
    • Important factors that restrict green plants to certain parts of the earth include:
    • • Temperature
    • • Soil
    • • Sunlight
    • • Water
    • • Plant eaters
    • These and additional considerations restrict animals to those parts of the earth where they can
    • survive. Some additional considerations are as follows:
    • • Food supply
    • • Mates
    • • Diseases
    • • Parasites
    • • Natural enemies
    • Energy captured by green plants is transferred from organism to organism in a pathway known
    • as a food chain. Each organism in the chain provides food for the next organism. For example:
    • Barley → Grasshopper → Spider → Frog → Fish → Bear
    • In this food chain, the bear is the predator, the fish is its prey; the fish is the predator, the frog is
    • its prey; and so on. An organism may be part of several food chains. Unconsumed dead organisms
    • at every level are broken down by decomposers, returning organic matter and minerals to the soil.
    • This entire process is the traditional method of recycling by natural forces. Ecosystems are
    • frequently unbalanced or destroyed as a result of human activities. Conservation of natural resources
    • and control of pollution of air, water, and soil will help preserve existing ecosystems.
  77. Biomes
  78. 1. Tundra: Located in the high northern latitudes of the world, is the coldest of all the
    • biomes. Because the ground is always frozen a few feet below the surface, there are no
    • deep root systems; the tundra is known for its treeless plains.
    • 2. Taiga: Located just south of the tundra. Contains mostly cold-tolerant evergreen trees.
    • Its seasons are divided into short, moist, and moderately warm summers and cold, dry
    • winters.
    • 3. Deciduous Forests: Located south of the taiga in eastern North America, northeastern
    • Asia, western and central Europe. Characterized by a moderate climate with distinct
    • winters. Its trees have broad leaves that are shed annually.
    • 4. Grasslands: Some locations include North American (the Great Plains) and the pampas
    • of South America. The grasslands are dominated by grasses rather than large shrubs
    • or trees due to insufficient rainfall.
    • 5. Tropical Rain Forests: Located near the equator and known for high temperatures
    • and constant rainfall. Trees grow very tall and form a thick layer of leaves (the canopy)
    • that greatly reduces light at ground level.
    • 6. Deserts: Deserts cover one-fifth of the earth’s surface and are characterized by extreme
    • dryness. Deserts may be hot or cold.
    • 7. Marine: This is the largest
    • part of the biosphere, since water covers almost 75 percent
    • of the earth’s surface.
  79. Cell Structures
  80. Cells are the basic structural unit of living things and develop from other cells. Protoplasm, or
    • living material, is contained within tiny cells. These cells differ in size and shape, depending on
    • their function in the body (see Figure 13 on page 118).
    • The major parts of cells and their functions follow.
    • 1. The nucleus is the control center for all cellular activity. Small dark bodies found in the
    • nucleus are called nucleoli. The protoplasm within the nucleus is called nucleoplasm.
    • Within the nucleoplasm are long, thin fibers called chromatin on which genes are found.
    • 2. The cytoplasm, the cells’ manufacturing area, contains small vacuoles, which are storage
    • areas and several other structures, or organelles.
    • 3. Ribosomes combine amino acids to build proteins. The cytoplasm contains many ribosomes.
    • 4. The cell membrane plays an important role in controlling the flow of materials entering
    • and leaving the cell. It is semipermeable and allows only certain materials to enter and
    • leave. The movement of particles from an area of high concentration to an area of lower
    • concentration until equilibrium is reached is termed diffusion.
    • 5. The endoplasmic reticulum is a membrane network that extends from the nucleus to
    • the cell membrane. It transports lipids and proteins through the cell.
    • 6. The Golgi body, or Golgi apparatus, prepares and stores chemical products produced in
    • the cell and then secretes them outside the cell.
    • 7. Lysosomes are saclike structures that contain and release enzymes necessary for
    • digesting certain substances within the cell.
    • 8. Mitochondria are complex organelles in the cell that produce energy via cellular
    • respiration to fuel the cell’s activities.
  81. Differences between Plant and Animal Cells
  82. Although all cells are similar in structure, plant and animal cells do differ. The major differences
    • are as follows:
    • • Plant cells have a firm outer boundary called the cell wall. This wall supports and
    • protects the plant cell.
    • • Vacuoles in the plant cell are much larger than those in the animal cell.
    • • Many plant cells contain within the cytoplasm small green structures called chloroplasts.
    • These chloroplasts contain chlorophyll that enables the plant cell to make
    • food.
  83. Cell Processes
  84. There are various processes carried out by the living cell. Some major examples are as follows:
    • • Water is the largest component of the cell protoplasm. Movement or diffusion of
    • water through a semipermeable membrane is known as osmosis.
    • • The sum of all chemical reactions within a living cell, both the building up and the
    • tearing down of complex molecules, is known as metabolism.
    • • Cells can also acquire material by engulfing particles. This process is termed phagocytosis.
    • Certain white blood cells protect the body from infection by this method.
    • Two vital cellular reactions are:
    • 1. Photosynthesis: The process by which green plants convert carbon dioxide and water
    • into sugar and oxygen. Both sunlight and chlorophyll are needed for this reaction.
    • The chemical reaction for photosynthesis is
    • 6CO 6H O C H O 6O 2 2
    • sunlight
    • chlorophyll 6 12 6 2 + ⎯⎯⎯⎯→ +
    • Note that six molecules of carbon dioxide combined with six molecules of water form one
    • molecule of sugar (glucose) and six molecules of oxygen. The energy obtained from the sunlight
    • is stored in the sugar produced.
    • 2. Respiration: The reverse of photosynthesis. Both animal and plant cells oxidize glucose
    • to form carbon dioxide and water.
    • The chemical reaction for respiration is
    • C H O O CO H O 6 12 6 2 2 2 + 6 ⎯⎯→6 + 6
    • Note that one molecule of sugar (glucose) combined with six molecules of oxygen form six
    • molecules of carbon dioxide and six molecules of water. The energy produced by this reaction is
    • used by the cell.
    • These are some of the more vital cell processes that enable the cell to carry out essential life
    • activities, such as obtaining food for energy, getting rid of waste materials, obtaining oxygen, and
    • building new material.
  85. Physical Science
  86. Chemistry is the science that deals with the structure, composition, and properties of substances.
    • It is also the study of elements and the compounds they form.
    • Classification of Matter into Elements and Compounds
    • Matter is anything that has mass and occupies space, although mass and weight are not the same.
    • Mass is the amount of matter an object contains. Weight is the pull of gravity on that mass. For
    • example, a 200-pound astronaut may be almost weightless in outer space without any reduction in
    • mass.
    • Elements
    • Matter is composed of basic substances known as elements. The atom is the smallest part of an
    • element that still acts like that element. The atom consists of a nucleus that contains neutrons and
    • protons in the center. They are surrounded by flying particles called electrons. Atoms are electrically
    • neutral as the positive protons neutralize the negative electrons. The number of electrons
    • outside the nucleus is the same as the number of protons in the nucleus. The neutrons in the
    • nucleus have no charge.
    • The negatively charged electrons outside the nucleus are arranged in energy levels. When
    • atoms bond to form substances, they complete their outer energy level. The first energy level
    • needs two electrons to be complete, the second energy level needs eight, etc.
    • Atomic Numbers
    • The number of protons in an atom determines its atomic number. The atomic number of hydrogen
    • is one because it has one proton in its nucleus. Helium has an atomic number of two because it has
    • two protons in its nucleus. Carbon has an atomic number of 6; oxygen has an atomic number of 8
  87. Periodic Table
  88. The periodic table classifies all elements. The elements, listed by increasing atomic number, are
    • arranged in vertical columns called groups or families. Each group contains elements with similar
    • chemical properties (see Figure 15 below).
    • Note that hydrogen, lithium, sodium, and potassium, all with one electron in the outermost energy
    • level, are in the same group. Helium, neon, and argon are in the group termed the noble
    • gases. They are rare gases that are completely inert—having completed outermost energy levels.
    • The first 22 elements are listed in the table on page 122. The listing includes the atomic number,
    • name, symbol, and electron distribution within energy levels.
    • Metals generally have three or fewer electrons in the outermost energy level and tend to give up
    • electrons readily (copper, magnesium, iron, etc.). Nonmetals have five or more electrons in the
    • outermost energy level and tend to hold them tightly (nitrogen, oxygen, chlorine, etc.).
  89. Compounds
  90. Substances composed of atoms of two or more different elements are called compounds. Hydrogen
    • atoms combine with oxygen to form a molecule of water (H2O). A sodium atom combines
    • with a chlorine atom to form an ionic particle of salt (NaCl). Properties of compounds differ
    • greatly from the properties of the atoms that form the compound. Common salt, a relatively
    • harmless substance, consists of sodium and chlorine, both highly toxic elements. The types of
    • compounds follow.
    • • Organic compounds are compounds containing carbon.
    • • Hydrocarbons contain hydrogen and carbon only. Methane, ethylene, acetylene, and
    • propane are hydrocarbons.
    • • Carbohydrates contain only carbon, hydrogen, and oxygen. Common carbohydrates
    • are sugars and starch. Glucose (C6H12O6) is a simple sugar. Sucrose (C12H22O11) or
    • cane sugar is a disaccharide or more complex sugar.
    • • Fats also contain carbon, hydrogen, and oxygen. Fats may be classified as saturated
    • or unsaturated compounds.
    • • Proteins contain carbon, hydrogen, oxygen, and nitrogen. Some proteins contain, in
    • addition, sulfur and phosphorus. Proteins consist of smaller molecules called amino
    • acids.
  91. chart
  92. 1 Hydrogen H 1
    • 2 Helium He 2
    • 3 Lithium Li 2 - 1
    • 4 Beryllium Be 2 - 2
    • 5 Boron B 2 - 3
    • 6 Carbon C 2 - 4
    • 7 Nitrogen N 2 - 5
    • 8 Oxygen O 2 - 6
    • 9 Fluorine F 2 - 7
    • 10 Neon Ne 2 - 8
    • 11 Sodium Na 2 - 8 - 1
    • 12 Magnesium Mg 2 - 8 - 2
    • 13 Aluminum Al 2 - 8 - 3
    • 14 Silicon Si 2 - 8 - 4
    • 15 Phosphorus P 2 - 8 - 5
    • 16 Sulfur S 2 - 8 - 6
    • 17 Chlorine Cl 2 - 8 - 7
    • 18 Argon Ar 2 - 8 - 8
    • 19 Potassium K 2 - 8 - 8 - 1
    • 20 Calcium Ca 2 - 8 - 8 - 2
    • 21 Scandium Sc 2 - 8 - 9 - 2
    • 22 Titanium Ti 2 - 8 - 10 - 2
  93. Mixtures
  94. A mixture consists of different types of matter near each other but not chemically bound to each
    • other. For example, granite rock has three different crystalline materials dispersed throughout the
    • rock—quartz, feldspar, and mica. They each retain their own unique properties in the mixture.
    • A solution is a mixture in which one type of molecule is dispersed throughout other molecules
    • (sugar and water). The resulting sugar solution has similar properties throughout.
    • A suspension is a mixture in which the dispersed particles are larger than molecules and
    • are dispersed throughout the system. Suspended particles eventually settle out (smoke).
    • A colloid is a mixture containing dispersed particles larger than molecules but small
    • enough not to settle out (gelatin).
  95. Characteristics of Solids, Liquids, and Gases
  96. The three different physical states in which matter normally exists are:
    • 1. Solids: A solid has a definite shape and a definite volume. It generally consists of small
    • crystals tightly joined together. The molecular particles in a solid are still in motion but to
    • a much lesser extent. Ice is the solid state of water. Aluminum and copper are solids.
    • 2. Liquids: A liquid has a definite volume but takes the shape of its container. Molecular
    • particles in a liquid move about but not rapidly. Mercury is a liquid.
    • 3. Gases: A gas has no shape and no definite volume. It is mostly empty space and can
    • readily be expanded or compressed by either pressure or temperature. Particles in a gas
    • move about rapidly. Steam is the gaseous state of water. Hydrogen and oxygen are
    • gases.
    • When molecular particles of a substance have little kinetic energy, the substance will be in a
    • solid state. If the solid is heated, the kinetic energy of the molecules increases and the physical
    • state changes from a solid to a liquid (ice to water). The temperature at which a solid substance
    • changes to a liquid is known as its melting point.
    • Further heating will increase the kinetic energy of the molecules still more and the physical state
    • will change from a liquid to a gas (water to steam). The temperature at which a liquid substance
    • changes to a gas is called its boiling point.
    • Lowering the temperature will change a gas to a liquid and a liquid to a solid. The temperature
    • at which a liquid changes to a solid is called the freezing point. Movement of particles in matter
    • ceases at absolute zero or –273ºC.
  97. Simple Solutions
  98. A solution is a mixture of one substance dissolved in another substance. The substance being
    • dissolved is the solute; the substance in which a solute is dissolved is the solvent. In a salt solution,
    • the salt (NaCl) is the solute, and water (H2O) is the solvent.
    • Solutes may be solids, liquids, or gases. Solvents are generally liquids. Water is the most common
    • solvent. Solutions may be classified according to the relative amounts of solute to solvent.
    • • A dilute solution contains a relatively small amount of solute dissolved in a large
    • amount of solvent.
    • • A concentrated solution contains a relatively large amount of solute dissolved in a
    • small amount of solvent.
    • • An unsaturated solution is a solution that can still dissolve more solute at the prevailing
    • temperature and pressure.
    • • A saturated solution is one containing the maximum amount of solute that can be
    • dissolved at a given temperature and pressure.
    • • A supersaturated solution is one that contains more solute than it can normally hold
    • at a given temperature.
  99. Acids and Bases
  100. Acids are substances that give up hydrogen ions (H+) when dissolved in water. Acids react with
    • metals and generally have a sour taste. Some common acids are hydrochloric acid, nitric acid, and
    • sulfuric acid used in industry; acetic acid found in vinegar; lactic acid found in milk; and citric acid
    • found in oranges and lemons.
    • Bases are substances that give up hydroxyl ions (OH) when dissolved in water. Bases generally
    • contain a metal (the one exception is ammonia). Some common bases are sodium hydroxide (lye)
    • used in making soap and ammonium hydroxide (ammonia) used as a cleaning agent.
    • When acids and bases react, neutralization occurs with the formation of water and a salt.
    • Hydrochloric acid plus sodium hydroxide yield common salt plus water:
    • HCl NaOH NaCl H O 2 + ⎯→⎯+
    • The pH of a solution is a number within the range of 1 to 14 that indicates the degree of acidity
    • or alkalinity. A pH of 7 indicates a neutral solution; less than 7 shows increased acidity; more than
    • 7 shows increased alkalinity.
  101. Simple Chemical Reactions
  102. Matter may change either by a physical change or by a chemical change. The form, size, or shape
    • of matter is altered in a physical change, but the molecules remain unchanged. Changing water
    • into ice or steam and dissolving sugar in water are examples of physical change. In a chemical
    • change, molecules of new matter are formed that are different from the original matter. The
    • burning of coal or the rusting of iron are examples of chemical change.
    • A chemical reaction is a reaction in which a chemical change occurs. The molecules that enter
    • the reaction are called reactants. The molecules resulting from the reaction are called products.
    • When charcoal burns, the following occurs:
    • Carbon plus oxygen produce carbon dioxide
    • carbon + oxygen⎯⎯→carbon dioxide
    • Using chemical symbols, the formula is:
    • C O CO 2 2 + ⎯→⎯This formula is the chemical equation for the oxidation of carbon. One atom of carbon combined
    • with one molecule of oxygen to form one molecule of carbon dioxide.
    • Using the reaction of hydrogen and oxygen to form water:
    • H O HO 2 2 2 + ⎯→⎯Note that this equation is not balanced; there are two oxygen atoms on the left side and only one
    • oxygen atom on the right.
    • H O 2H O 2 2 2 + ⎯→⎯But now the hydrogen atoms are not balanced. There are 4 hydrogen atoms on the right but only
    • 2 on the left. This is corrected by placing “2” in front of the H2 on the left side.
    • 2H O 2H O 2 2 2 + ⎯→⎯Is the following equation balanced?
    • H Cl HCl 2 2 + ⎯→⎯No, it is not. There are 2 atoms of hydrogen and 2 atoms of chlorine on the left side but only 1
    • atom of hydrogen and 1 atom of chlorine on the right side.
    • This equation can be balanced by placing a “2” in front of the HCl.
    • H Cl 2HCl 2 2 + ⎯→⎯There are four types of chemical reactions:
    • 1. Synthesis: two or more elements or compounds unite to form one compound:
    • carbon oxygen carbon dioxide
    • C+O CO 2 2
    • + ⎯→⎯⎯→⎯calcium oxide carbon dioxide calcium carbonate
    • CaO+CO2
    • + ⎯→⎯⎯→⎯CaCO3
    • 2. Decomposition: a substance breaks down into two or more substances:
    • Peroxide decomposes into water and oxygen
    • 2H O 2H O O 2 2 2 2
    • 3. Single displacement: one element displaces another in a compound.
    • 2KBr Cl 2KCl Br 2 2 + ⎯→⎯+
    • Chlorine displaced the bromine in the compound potassium bromide.
    • 4. Double displacement: the positive part of each reactant unites with the negative part
    • of the other reactant.
    • 3NaOH FeCl 3 NaCl Fe(OH) 3 3 + ⎯→⎯+
    • Sodium hydroxide reacts with ferric chloride to form sodium chloride and ferric hydroxide
  103. Measurement
  104. Measurement is an essential part of chemistry. Although the English system of measurement is
    • used in everyday life in the United States, most of the people in the rest of the world, as well as
    • scientists, use the modernized form of the metric system, a decimal system based on tens, multiples
    • of tens, and fractions of tens.
    • Length
    • The meter is the standard unit of length in the metric system. The meter (m) may be divided into
    • 100 equal parts called centimeters (cm).
    • 100 cm = 1 m
    • The meter (m) may also be divided into 1,000 equal parts called millimeters (mm).
    • 1 m = 100 cm = 1,000 mm
    • 1 cm = 10 mm
    • Distances of considerable length are measured in kilometers (km).
    • 1 km = 1,000 m
    • Changing from one unit to another is done by simply dividing or multiplying by
    • multiples of 10.
    • Area
    • Area is calculated by multiplying length by width. The area of a rectangle 3 meters long and 4
    • meters wide is 12 square meters.
    • 3 m × 4 m = 12 m2
  105. Volume
  106. Volume is the amount of space an object occupies. If the object is a cube or rectangular solid, the
    • volume is obtained by multiplying length × width × height. The cubic meter is a standard metric
    • unit of volume. However, it is a large unit containing 1 million cubic centimeters. The liter (L),
    • equal to 1,000 cubic centimeters, is the metric unit commonly used. The milliliter (mL) is used for
    • measuring still smaller volumes.
    • 1 liter (L) = 1,000 milliliters (mL)
    • 1 mL = 1 cm3
    • Mass
    • The more important units of mass in the metric system are the gram (g), kilogram (kg), and
    • milligram (mg).
    • 1 kg = 1,000 g = 1,000,000 mg
    • 1 g = 1,000 mg
  107. metric units
  108. × 1,000 kilo- (kilometer, kiloliter, kilogram) km, kL, kg
    • × 100 hecto- (hectometer, hectoliter, hectogram) hm, hL, hg
    • × 10 deka- (dekameter, dekaliter, dekagram) dam, daL, dag
    • × 1 (meter, liter, gram) m, L, g
    • × 0.1 deci- (decimeter, deciliter, decigram) dm, dL, dg
    • × 0.01 centi- (centimeter, centiliter, centigram) cm, cL, cg
    • × 0.001 milli- (millimeter, milliliter, milligram) mm, mL, mg
  109. Temperature
  110. Temperature is generally measured in scientific work by using the Celsius or centigrade scale.
    • This temperature scale is based on the freezing and boiling points of water. The freezing point is at
    • 0°C; the boiling point is at 100°C.
    • The Fahrenheit scale, used in everyday activities, is also based on the freezing and boiling points
    • of water. The freezing point is at 32°F; the boiling point is at 212°F.
    • Use the following formulas to change from one scale to the other:
    • ° = ° − °
    • ° = ° °
    • C F
    • F C+32
    • 5
    • 9
    • 32
    • 9
    • 5
    • The Kelvin or absolute scale of temperature is also used in scientific work. This scale starts
    • with absolute zero at –273°C. To change Celsius or centigrade temperature to Kelvin or absolute
    • temperature, add 273°.
    • K = °C + 273°
  111. Physics
  112. Physics is the science of matter, energy, and their interactions. These are grouped into many
    different fields, such as mechanics, thermodynamics, magnetism, and electricity.
  113. Force and Work
  114. A force is the push or pull that forces an object to change its speed or direction. Weight is the
    • force of gravity on an object. Work done on an object is defined as the force exerted on the object
    • times the distance moved in the direction of the force.
    • If W F d
    • W Fd
    • = = =
    • =
    • work; force; and distance,
    • The unit of work in the British system is expressed in foot-pounds (ft-lb). In the metric system,
    • the unit of work is the newton-meter (n-m) or joule (j).
    • Power is the rate of doing work.
    • Power
    • Work
    • Time
    • =
    • If P = Power; W = work; and t = time,
    • P
    • W
    • t
    • Fd
    • t
    • = =
    • In the British system, power is expressed in foot-pounds per second or foot-pounds per minute.
    • In the metric system, power is expressed in newton-meters per second or joules per second (also
    • known as watts). Machine power is generally expressed in horsepower. One horsepower is
    • equal to 550 ft-lb/sec.
  115. Newton’s Laws
  116. Sir Isaac Newton was an English physicist, philosopher, and mathematician. He formulated the
    • three laws of motion that explain how objects move in response to forces and a law to explain the
    • force of gravity as follows:
    • 1. Newton’s first law of motion predicts the behavior of objects for which all existing
    • forces are balanced. If the net force acting on an object is zero, the object will remain at
    • rest or remain moving at a constant velocity. If the force exerted on an object is zero, the
    • object does not necessarily have zero velocity. Without any forces acting on it, including
    • friction, an object in motion will continue to travel at constant velocity. In simpler terms,
    • an object at rest tends to stay at rest, and an object in motion tends to stay in motion with
    • the same speed and in the same direction unless acted on by an unbalanced force.
    • 2. Newton’s second law of motion pertains to the behavior of objects for which all existing
    • forces are not balanced. The net force acting on an object equals the product of the mass
    • and the acceleration of the object. A net force on an object will accelerate it or change its
    • velocity, and the direction of the force is the same as that of the acceleration. The mass
    • (m) of the object is measured in kilograms. Acceleration (a) is measured in meters per
    • second per second. Force (f) is measured in newtons. A newton is the force necessary to
    • impart a mass of 1kg an acceleration of 1/m/sec/sec. This theory is illustrated by the
    • following equation: F = ma. Note that this law is also known as the law of inertia since the
    • greater the mass of an object, the greater the force needed to overcome its inertia (its
    • reluctance to change velocity).
    • 3. Newton’s third law of motion. An object experiences a force because it is interacting
    • with some other object. When an object exerts force on another object, the second
    • object exerts on the first a force of the same magnitude but in the opposite direction.
    • Simply stated, for every action, there is an equal and opposite reaction.
    • 4. Newton’s law of gravity states that all objects in the universe attract each other with a
    • force that varies directly as the product of their masses and inversely as the square of
    • their separation from each other. The force is known as gravity, the fundamental force
    • responsible for interactions that occur because of mass between particles of matter.
    • Note that the earth’s, the moon’s, and planets’ attraction for objects is known as gravity.
  117. Speed
  118. Speed is a scalar quantity (a quantity that is fully described by a magnitude alone), which refers to
    • how fast an object is moving or the distance an object travels per unit of time. A fast-moving
    • object has a high speed, where as a slow-moving object has a low speed. An object with no
    • movement at all has no speed.
    • Speed = distance
    • time
  119. Velocity
  120. Velocity is a vector quantity (a quantity that is fully described by both a magnitude and a direction)
    • that refers to the rate in which an object changes position. Acceleration is the rate of change of
    • velocity. Velocity is also called momentum. Note that if an object is heavy, it will be difficult to stop
    • it or change its direction.
  121. Machines
  122. Machines are devices for transferring energy. Simple machines are generally used to change the
    • size or direction of a force.
    • Machines may be divided into the following classes:
    • • Lever (see-saw, crowbar, hammer, scissors, pliers, and shovel
    • • Inclined plane (screw and wedge)
    • • Wheel and axle (doorknob and steering wheel)
    • • Pulley (elevator and power shovel)
    • The jackscrew—a screw-operated jack used for lifting something or adjusting its position—
    • combines the lever and the inclined plane.
    • Efficiency
    • Output Work
    • Input Work
    • = ×100
    • The force applied to a machine to do the work needed is known as effort. The greater the force
    • that is applied, the greater the work that is done. The force that one must overcome is known as
    • resistance.
  123. Energy
  124. Energy may be defined as the capacity to do work and can be either kinetic or potential. Kinetic
    • energy is the energy possessed by a moving object. Potential energy is the work that can be done
    • by an object because of its relative position. Energy is found in many different forms, such as the
    • following:
    • • Chemical
    • • Heat
    • • Electrical
    • • Light
    • • Sound
    • • Mechanical
    • • Nuclear
    • Energy is neither created nor destroyed but can readily be changed from one form to another.
    • This is known as conservation of energy. For example, chemical energy is changed to electrical
    • energy with the storage battery. Friction may be used to change mechanical energy to heat. The
    • radio may be used to change sound to electrical energy and electrical energy to sound. Note that
    • some energy will be lost in the form of heat when energy is converted.
  125. Heat Transfer
  126. There are three methods by which heat is transferred from one object to another. These are
    • conduction, convection, and radiation.
    • 1. Conduction is the simplest method of heat transfer. It is accomplished by direct contact,
    • such as placing your finger on a hot object. The heat is transferred directly from the
    • hot object to the skin on your finger. Metals are generally good conductors of heat.
    • Other materials, such as wood or plastic, are poor conductors and are termed insulators.
    • Note that many metallic pots and pans have wooden handles that act as heat
    • insulators.
    • 2. Convection is the transfer of heat in liquids or gases when heated unevenly. The heated
    • liquid or gas rises and the resulting movement is termed convection
    • 3. Radiation of heat, such as the heat from the sun, is transmitted by electromagnetic
    • waves, which change into heat when they reach their destination.
  127. Basic Electricity
  128. There are two kinds of electric charge. One is positive (+); the other is negative (–). How objects
    • become electrically charged may be explained by electrons, negatively charged particles of matter.
    • When two objects are rubbed together, electrons are taken away from one object and added to
    • the other object. Combing your hair results in electrons moving from your hair to the comb, which
    • then takes on a negative charge.
    • Protons are positively charged particles. Matter is generally neutral, because it contains an
    • equal number of electrons and protons. The flow of electrons from one place to another results in
    • electric current. Metallic materials allow electrons to flow freely. These materials are called
    • conductors (copper, iron, silver, aluminum, etc.).
    • Materials that do not allow the free flow of electrons are called insulators (air, rubber, wood,
    • plastic, etc.).
  129. Circuits
  130. An electric circuit is the path along which electrons move from a place where there are many
    • electrons to a place where there are fewer electrons. It consists of many parts, including the
    • power source, conductors, switches, and the appliance or appliances to be operated. The circuits
    • may be in series or in parallel (see Figure 16 and Figure 17 on page 132).
    • In a series circuit, all parts are connected in a continuous line, one after another. If any part fails
    • or is switched off, all other parts are turned off. For example, when using series-circuited lights to
    • decorate a Christmas tree, one burned-out light will cause all the other lights on the tree to become
    • unlit by breaking the flow of electrons in the circuit.
    • In a parallel circuit, the different parts are on separate branches and can be switched off
    • without affecting the parts on the other branches.
    • There are two kinds of electric current:
    • 1. Direct current (DC): electrons flow in one direction only. With the dry cell, the electrons
    • move from the negative connector to the positive connector.
    • 2. Alternating current (AC): alternating current generated in power stations changes direction
    • many times per second. The electricity is produced by electromagnetic induction
    • resulting from motion in a magnetic field.
  131. The following terms are used in measuring electricity:
  132. • Volt: measures the amount of work done when electrons are moved between two
    • points in an electric circuit.
    • • Ampere: measures the amount of electrons moving past a certain point in a current in
    • one second.
    • • Ohm: the unit of measurement of resistance, which consists of all conditions in an
    • electric circuit that limit the flow of electrons. An electric circuit with a current of 3
    • amperes and a resistance of 4 ohms would have a voltage of 12. Ohm’s law states:
    • Volts = Amperes × Ohms
    • • Watt: measures how much electricity is consumed. The amount of electricity used
    • and the length of time used is measured in watt-hours for small amounts of energy or
    • kilowatt-hours for larger amounts. A kilowatt-hour is the amount of energy used in
    • one hour by one kilowatt of power.
    • • Ammeter: used to measure the amount of current in amperes.
    • • Voltmeter: used to measure potential difference in volts.
    • Fuses and circuit breakers are devices that limit current flow. In the fuse, a small section of
    • wire will melt and break the current if a certain amount of electric current passes through it.
    • Current capacity of the fuse is determined by the size (thickness) of the wire. Circuit breakers
    • interrupt the flow of current mechanically when the current limit is reached.
  133. Magnetism
  134. Simple magnets have two poles—a north pole and a south pole. If the north poles of two magnets
    • are brought close together, they will repel one another. If the south poles of two magnets are
    • brought together, they will also repel one another.
    • If the north pole of one magnet is brought close to the south pole of another magnet, they will
    • attract one another (see Figure 18 on page 134). The force of attraction or repulsion is called
    • magnetic force. The magnetic poles are the two locations on the magnet where magnetic forces
    • are strongest.
    • The region surrounding the magnet where there is a magnetic force is called the magnetic field.
    • Lines of force extend from one pole to the other pole of the magnet with the greatest force
    • concentrated at the poles (see Figure 19 on page 134).
    • When a wire is moved in a magnetic field, current is produced in the wire. This effect, known as
    • electromagnetic induction, led to the development of generators. The electric generator produces
    • current that flows in one direction and then in the opposite direction, producing an alternating
    • current.
    • The strength of the magnetic force between two objects increases as the amount of electric
    • charge on these objects increases. The strength of the magnetic charge between the objects
    • decreases as the distance between them increases. Reducing the distance between the two objects
    • by a half results in a magnetic force four times as great. For example, reducing the distance
    • from 100 mm to 50 mm increases the magnetic force fourfold. Similarly, increasing the distance
    • from 100 mm to 200 mm reduces the force to one fourth the original amount.
    • The magnetic compass contains a magnetic needle that rotates in a horizontal direction. The
    • compass case is always made of a nonmagnetic substance, usually brass.
  135. Light
  136. Although light possesses many properties of waves (reflection, refraction, etc.), it differs somewhat
    • from other waves. Compared with sound waves, light waves are much faster and can travel
    • through empty space. Light or other waves that can travel through space at very high speed are
    • called electromagnetic waves.
  137. The different types of electromagnetic waves in increasing order of frequency and decreasing
    wavelength are as follows:
  138. • Ordinary radio waves
    • • FM and television waves
    • • Radar and microwaves
    • • Infrared waves
    • • Light waves
    • • Ultraviolet waves
    • • X-rays
    • • Gamma waves
  139. Two important characteristics of light are:
  140. 1. Light waves generally move in a straight path at approximately 186,000 miles per second.
    • 2. Light may change its direction when moving from one material to another material (for
    • example, from air to water).
    • Refraction occurs when light waves are bent (change direction) passing from one material into
    • another. Refracted light can cause mirages or false illusions.
    • Sunlight is a mixture of all the colors of the rainbow—a spectrum. When sunlight is passed
    • through a prism, the colors are separated into a spectrum of red, orange, yellow, green, indigo, and
    • violet.
    • Reflection occurs when light rays strike a flat mirror and bounce off. The rays striking the
    • mirror are called incident rays; those that bounce off are termed reflected rays.
    • Lenses refract light rays in different ways
  141. Sound
  142. References to sound in physics are really references to sound waves. These are waves in gases,
    • liquids, and solids that cannot be transmitted through a vacuum or empty space. There are three
    • important properties of sound waves:
    • 1. Wavelength is the distance between high points or between low points and is generally
    • measured in millimeters or centimeters.
    • 2. Speed is determined by measuring how fast the waves move. That is, how fast the high
    • point (crest) or low point (trough) moves. Speed is generally measured in meters per
    • second (see Figure 21).
    • Frequency is determined by measuring the number of waves (crests or troughs) that move past
    • a certain point in one second. The unit of measurement is the hertz (Hz). One hertz is one wave
    • moving past per second.
    • The relationship of these properties of sound may be shown by the formula:
    • Wavelength
    • Speed
    • Frequency
    • =
    • Sound waves have a vibrating or back-and-forth motion. They do not move as fast in air as in
    • water. Similarly, sound waves do not move as fast in water as they do in wood or metals. A train
    • approaching from the distance can be heard at a greater distance by the noise through the steel
    • rails than by the noise made through the air.
    • The pitch of sound is closely related to the frequency of the sound waves. A high sound frequency
    • is called a high pitch. The volume, or loudness of a sound, is determined by the amplitude
    • of sound waves. The intensity of sound is expressed on a decibel scale. The amplitude and frequency
    • of sound waves determine the sound intensity.
  143. Earth Science
  144. This section includes several sciences that fall into the category of earth sciences. These include
    • the basics of meteorology and astronomy.
    • Geology
    • The earth consists of three layers—the crust, the mantle, and the core:
    • 1. The crust is a thin layer and compromises the earth’s surface. It varies in thickness
    • from a few miles beneath the oceans to nearly 50 miles beneath the Himalaya and
    • Tibetan Plateau.
    • 2. The mantle is the thick layer beneath the crust and represents more than 80 percent of the
    • earth’s volume. The mantle consists of solid rock. However, the top portion of the mantle
    • has areas capable of sudden movement or continuous, slow movement.
    • 3. The core is the earth’s center and comprises almost 20 percent of the earth’s volume.
    • The temperature of the earth’s outer core is estimated to be between 3,500º C and 4,700º C.
    • This heat is prevented from escaping by the solid rock in the upper mantle and the crust. Cracks
    • in the earth’s crust produce faults. Earthquakes are caused by the movement of rocks along
    • faults. The waves produced by earthquakes can be recorded by a seismograph. The intensity of
    • earthquakes is measured on a 1 to 10 scale called the Richter scale.
  145. Rocks
  146. and degree of hardness. The natural mechanical and chemical processes that break rock into
    • smaller pieces are termed weathering. Temperature changes, frost action, and plant root growth
    • are common forms of mechanical weathering. Oxidation and action of air pollutants causes chemical
    • weathering.
    • The natural processes that cause the smaller pieces of rock to be carried away are termed
    • erosion. Erosion is generally accomplished by running water, wind, and glaciers.
    • Based on their method of formation, the three classes of rock are igneous, sedimentary, and
    • metamorphic.
    • Igneous rock is formed by the cooling and hardening of molten material. Granite and pumice
    • are two common igneous rocks.
    • Sedimentary rock is formed by the joining together of small pieces of rock or sediment deposited
    • when fast-moving streams slow down. The sediment may consist of different sized particles
    • or pieces ranging from mud to gravel. In time, these particles may become compressed or cemented
    • together to form sedimentary rock. Shale, sandstone, limestone, and soft coal are common
    • types of sedimentary rock.
    • Metamorphic rock is formed by changes resulting from great heat, pressure, and time. Both
    • sedimentary and igneous rock may become metamorphosed. Slate, marble, and hard coal are
    • common kinds of metamorphic rock.
    • Rocks beneath the earth’s crust that are heated to the melting point are called magma. When
    • the molten magma reaches the earth’s surface, it is called lava. A volcano is the rock formation
    • that results when lava reaches the earth’s surface.
  147. Meteorology
  148. The earth’s atmosphere consists of layers of air surrounding Earth’s surface (see Figure 22).
    • These gaseous layers are:
    • • The troposphere is the first or innermost layer of the atmosphere and extends five to
    • ten miles above the earth’s surface. We live in this layer where virtually all weather
    • changes and cloudiness occur. Most of the air surrounding the earth is found in this
    • layer.
    • • The second layer is the stratosphere and extends up to about 25 to 30 miles above
    • the earth.
    • • The third layer is the mesosphere, which extends to about 50 miles above the earth.
    • • The fourth or outermost layer is the thermosphere, which extends to approximately
    • 350 miles above the earth. Air in this layer is extremely thin.
    • • The ionosphere is the layer between the mesosphere and the thermosphere. This is
    • an important communication zone as it reflects various types of radio waves.
    • Almost half of the sun’s radiation passes through the atmosphere and reaches the earth’s surface
    • where it is absorbed by the land and the water of the oceans, which warm the air above
    • them. Land absorbs energy and warms up faster than water. Accordingly, during the daytime, air
    • over land gets warmer than air over water; at night, air over land gets cooler than air over water.
    • These temperature differences cause differences in air density.
    • The sun’s rays strike the earth’s surface at different angles. The equator receives direct rays,
    • whereas the regions closer to the poles receive slanted rays. This also affects the air temperatures
    • and causes differences in air density.
  149. Air Pressure
  150. The force with which air presses on the surface of the Earth is known as air pressure. Cold air is
    • denser and presses down with greater pressure (high pressure). Warm air is less dense and
    • presses down with less pressure (low pressure). A mercury barometer uses a thin tube of mercury
    • to measure atmospheric pressure. At sea level, air pressure will normally support about 30
    • inches of mercury. This pressure may also be expressed as about 15 pounds per square inch.
    • Air generally flows from high pressure to low pressure. This air movement is called
    • wind. Wind direction is identified by using a weather vane. Wind velocity is measured by an
    • anemometer.
  151. Humidity
  152. The sun’s energy evaporates the oceans’ water, producing vapor. Humidity is the amount of
    • water vapor in air. Relative humidity is the amount of moisture in the air compared to the maximum
    • amount it can hold at that temperature. Relative humidity is measured by means of a hygrometer
    • consisting of a wet-and-dry bulb thermometer.
    • Most people find a relative humidity of 50 to 60 percent at normal room temperature to be quite
    • comfortable. Air is saturated when it contains the maximum amount of water vapor it can hold at
    • a given temperature. The temperature at which the relative humidity reaches 100 percent is called
    • the dew point, the temperature at which the vapor will begin to condense into a liquid.
  153. Clouds
  154. Clouds have different shapes and sizes. The three basic types of clouds are stratus, cumulus, and
    • cirrus.
    • 1. Stratus clouds are broad, flat, low-hanging clouds that blanket the sky. Darkened stratus
    • clouds indicate that rain will soon fall.
    • 2. Cumulus clouds are massive clouds having flat bottoms and rounded tops. They resemble
    • white smoke rising from a smokestack and indicate fair weather. When cumulus
    • clouds darken and greatly increase in size, expect heavy rains.
    • 3. Cirrus clouds are high, thin, feathery clouds. The presence of such clouds indicates the
    • possibility of rain or snow within a few days
  155. Air Masses
  156. Air masses have characteristics related to the region where they are formed. Air masses formed
    • over land are dry; those formed over oceans are humid. Air masses formed in the northern regions
    • of the northern hemisphere are cold; those formed at or near the equator are warm.
    • When two different air masses meet, they do not readily mix but form a boundary of separation
    • called a front. When a cold air mass encounters a warm air mass, a cold front is created. The
    • warmer air mass is pushed aside, cumulus clouds form, and there are heavy showers. When a
    • warm air mass encounters a cold air mass, a warm front is created. The warm air passes over the
    • cold air forming cirrus clouds. In time, the clouds thicken and move closer to the earth, causing
    • precipitation and, sometimes, lingering fog.
  157. Astronomy
  158. Astronomy is the study of the stars, planets, and other heavenly bodies.
    • The earth’s orbit around the sun is termed an ellipse, a slightly flattened circle. As the earth’s
    • axis (an imaginary line running through the earth from pole to pole) is not perpendicular to the
    • orbit, but tilted at an angle of 23
    • 1
    • 2
    • °
    • , the North Pole is tilted toward the sun during part of the orbit
    • and tilted away from the sun during another part of the orbit. This explains why daylight and
    • darkness are not of equal length except on the first day of spring (vernal equinox) and the first day
    • of autumn (autumnal equinox).
    • The earth spins on its axis and makes a complete rotation every 24 hours. It revolves around the
    • sun every 365
    • 1
    • 4
    • days, necessitating a leap year every four years. The earth revolves and rotates
    • in the same direction from west to east.
    • The moon is a satellite of the earth. It makes a complete orbit around the earth every 27
    • 1
    • 3
    • days,
    • turning once on its axis during this period. The moon is the earth’s nearest neighbor. A lunar
    • eclipse occurs when the moon moves into the earth’s shadow. A solar eclipse occurs when the
    • earth moves into the moon’s shadow.
    • Solar System
    • The solar system consists of the sun and a multitude of smaller bodies held in orbit by the sun’s
    • huge mass. It is called the solar system because the sun’s huge mass and its resulting force of
    • gravity control the movement of these smaller bodies.
    • The nine planets in the solar system are among its largest bodies. Six of the planets (Earth,
    • Mars, Jupiter, Saturn, Uranus, and Neptune) have satellites.
    • There are four smaller planets closest to the sun frequently called the inner planets. These are:
    • • Mercury
    • • Venus
    • • Earth
    • • Mars
    • The five planets farthest from the sun are frequently termed the outer planets. Except for Pluto,
    • which is the second smallest planet after Mercury, the outer planets are far larger than the inner
    • planets. The outer planets are:
    • • Jupiter
    • • Saturn
    • • Uranus
    • • Neptune
    • • Pluto
    • Some of the small bodies in the solar system collide with the earth. Most of these bodies burn up
    • because of the friction of the earth’s atmosphere. These bodies are called meteors or “shooting
    • stars.” Those that reach the earth’s surface are termed meteorites.
    • The North Star, or Polaris, is a most important star because it is virtually in direct line with the
    • North Pole of the earth and therefore appears to remain stationary in the sky. This star has long
    • been used by navigators as a directional guide.