Chapter 10 Glossary Terms

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Chapter 10 Glossary Terms
2014-10-13 16:35:44
msday science

Chapter 10 Glossary Terms
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  1. What is electricity?
    A form of energy that results from the interaction of charged particles, such as electrons or protons.
  2. What is static charge (static electricity)?
    An electric charge that tends to stay on the surface of an object, rather than flowing away quickly. This builds up when different materials rub together. e.g. in a clothes dryer.
  3. What is charging by friction?
    A process in which objects made from different materials rub against each other, producing a net static charge on each. e.g. in a clothes dryer, different materials rub together, causing a static charge. Another example is rubbing a rubber balloon against a sweater. One material will have a stronger attraction to electrons (which makes them negatively charged) than the other, and will pull electrons off the other material (which would be positively charged).
  4. What is an electrostatic series?
    A list of materials that have been arranged according to their ability to hold on to electrons. It is based on data from experiments. By rubbing two materials, scientists determine whether an object is negatively or positively charged. In an electrostatic series, materials that have a weaker hold on electrons are at the top, while objects with a stronger hold are at the bottom. e.g. glass has a weak hold on electrons, so it would be at the top of an electrostatic series.
  5. What is an insulator?
    A material in which electrons cannot move easily from on atom to another. Materials that have a weak hold in an electrostatic series can be classified as an insulator. e.g. wood, rubber and plastic.
  6. What is a conductor?
    A material in which electrons can move easily between atoms. In an electrostatic series, a conductor is usually a material that has a strong hold on electrons. e.g. copper, aluminum and mercury.
  7. What is a semiconductor?
    A material in which electrons can move fairly well between atoms. e.g. silicon.
  8. What is a ground?
    An object that can supply a very large number of electrons to, or can remove a very large number of electrons from, a charged object, therefore neutralizing the object. This is the simplest way to remove the net static charge on an object. It gives electrons to positively charged objects and takes them away from negatively charged objects. The object then becomes neutral. A conductor becomes 'grounded' when electrons a free to flow between the conductor and Earth. By touching charged objects you can ground them.
  9. What is an electroscope?
    A device for detecting the presence of an electric charge. e.g. pith ball electroscope and metal leaf electroscope.
  10. What is charging by contact?
    Generating a charge on a neutral object by touching it with a charged object. e.g. a neutral pith ball and a negatively charged object. When the make contact, electrons flow from the negatively charged object into the pith ball. There is a reduced charge in the object, and the pith ball becomes negatively charged.
  11. What are laws of electric charges?
    Laws that describe how two objects interact electrically when one or both are charged. The three laws are: like charges repel, opposite charges attract, and charged and neutral objects attract each other.
  12. What is an electric field?
    A property of the space around a charged object, where the effect of its charge can be felt by other objects. Objects with greater net charges have stronger electric fields, and the farther the distance from the charged object, the weaker the electric field of the object is. All electric forces between two objects are transmitted through the electric field at the speed of light.
  13. What is induced charge separation?
    The movement of electrons in a substance, caused by the electric field of a nearby charged object, without direct contact between the substance and the object. When a charged object exerts a force on the protons and electrons in a substance, it induces electrons in a neutral object to move, closer or further away from the charged object.
  14. What is an ion?
    A charged atom or group of atoms. These are formed when raindrops, ice particles, or hailstones collide, in which charge is transferred.
  15. What is a lightning rod?
    A metal sphere or point, attached to the highest part of a building and connected to the ground. A copper wire connects the lightning rod to a metal plate or bare metal cable in the ground. It is important in rural areas where a house or barn is the tallest building.
  16. What is an electrostatic precipitator?
    A type of cleaner that removes unwanted particles and liquid from a flow of gas. This was invented by Frederick Cottrell. The electrostatic precipitator can be very effective for reducing pollution from smokestacks.
  17. What is the Van de Graaff generator?
    A device that accumulates very large charges. The sphere of the generator rests on an insulated column, in which a rubber belt runs over two rollers. A motor drives the lower roller, and charging by friction takes place as the belt moves over it. The charges on the belt are carried up as the belt rotates. A metal collecting comb is near the top roller, which the charged belt induces a redistribution of charges in. Charges then accumulate on the metal sphere.
  18. What is a radiation dosimeter?
    A small device that detects and measures exposure to radiation. People need to wear a radiation dosimeter when working with radioactive materials, as well as astronauts from the radiation of the Sun.