Card Set Information
First exam in 2001
What are the steps to the scientific method?
1. Problem - make observation
2.Hypothesis - A statement solving the problem or explaining the observation
3. Experiment - test the hypothesis
4. Results - analyze and repeat the test
5. Conclusion - accept or reject hypothesis
Define Hypothesis -
Possible explanation of a natural event or observation.
Define Theory -
A well-sustained explanation of some aspect of the natural world (that can incorporate scientific facts, laws, and tested hypothesis.
Define Law -
A descriptive generalization about how some aspect of the natural world behaves under stated conditions.
Explain why a control group is necessary and what is the difference between it and the experimental group
identical to the experimental group EXCEPT does not experience the test or treatment.
Used for comparison.
What is the difference between independent and dependent variables?
The independent variable is the one being changed or manipulated (on purpose) in an experiment. (input)
The dependent variable is the observed result from manipulating the independent variable. (output)
Length units and define -
Meters (m) defined based on speed of light
Mass units and define -
Kilogram (kg) defined based on a platinum cylinder housed in Paris.
Time units and define -
Seconds (s) defined based on the vibrations of a Cesium atom (atomic clock); which is incredibly accurate.
Define kilo, centi, milli, micro, nano?
kilo - one thousand time base unit (1000 x base)
centi - one-hundredth times base unit (.1 x base)
milli - one-thousandth times base unit (.001 x base)
micro - one-millionth times base unit (.000001 x base)
nano - one-billionth time base unit (.000000001 x base)
Define Astronomy -
Oldest Science (study of the stars, planets, and other objects in outer space)
What is a star? Describe its properties and characteristics.
Star - ball of burning gas
Fusion reactor in space - Nuclear reaction
Ball of gas held together by gravity
Most abundant elements in the universe
Hydrogen H2 - is the major fuel for stars
Describe the electromagnetic spectrum and which electromagnetic radiation penetrates the Earth's atmosphere?
Radio - Earth (Longest wave length with low frequency)
Microwave - Earth
Infrared - Earth (some)
Visible light - Earth
X - rays
Gamma (shortest wavelength with high frequency)
What is the difference between Refracting and Reflecting telescopes?
Refracting - bends light and uses lenses
Reflecting - Uses mirrors to reflect and focus light to form an image
Who was the first scientist to use a telescope for Astronomy?
Galileo - blinded by the sun
What is the largest telescope and where is located?
Gran Telescopio Canarias - Canary Islands
Describe the Hubble Space Telescope, Chandra X-ray telescope, the Spitzer Infrared Telescope and the Fermi?
Hubble - 1990 2.4m mirror visible and ultra violent light.
Chandra - named after scientist, first to understand the final stages in the lives of stars, stop sign from 12 miles away.
Spitzer - In order not to take its own picture the telescope must be cooled in bath of liquid helium
Fermi - explores black holes and neutron stars
List label of Sun in order from center to outer -
When can the chromosphere and corona be seen?
During an eclipse.
Which part of the sun do we actually see?
How old is the sun, where is it in its life cycle?
Age - 4.5 billion years
Halfway through its life span
What is the distance between the earth and sun in miles and km?
93 million miles or 150 million km
How long does it take light from the sun to reach the earth?
What is nuclear fusion and where does it occur?
Nuclear reactions are collision of high energy gamma rays and x-rays. Occurs in the Core
What color of stars and the coolest and the hottest?
Coolest - Red
Hottest - Blue / White
Define luminosity or brightness -
Total energy emitted by a star
Define Absolute Brightness -
Brightness of star if viewed from a standard (the same) distance.
Define Apparent Brightness -
Brightness of a star as viewed from Earth
Define Light year and how many km and miles make one light year?
Distance light travels in one year
10 trillion km / 6.2 trillion miles (1 x 10^12)
How much is a trillion, billion, million?
Trillion - 12 zeros
Billion - 9 zeros
Million - 6 zeros
Know the Hertzsprung-Russell diagram -
Describe Laplace's Nebular Hypothesis -
1. 4.5 billion years ago
2. Nebula (Large cloud of dust & gas - mainly H2 very little He)
3. Began to collapse and spin because of gravity
4. Material collected in the center became hot and dense, forming a protostar
5. The outer material formed the planetismals which became the planets
What are the life spans of stars smaller, about the same mass and larger than the sun?
Smaller - glows about 100 billion years
Same - Red giant begins collapse to white dwarf
Larger - Catastrophic collapse - supernova
What is a nebula?
clouds of gas and dust (distant cluster of stars)
The Great Debate -
Shapley - One large galaxy with spiral nebulae / gas cloud
Curtis - made up of many galaxies. Spiral nebulae.
Hubble - discovered billions of galaxies
Define cosmology -
Study of the structure, history and evolution of the universe. (More theory based)
Name and define the 4 types of galaxies?
Spiral - 100,000 Light years across 75% brighter.
Elliptical - Oval shaped, Largest
Irregular & Dwarf - Fainter & harder to detect (most common)
Active Galaxies (quasars) - very bright, black hole center / most distant
What type of galaxy are we a part of and what is its name?
Spiral - Milky Way
What is the Red Shift? Hubble's conclusion?
Nearby galaxy emitting colors shifted towards red. (Doppler Effect)
Galaxies were moving away from Earth. The further away - the faster it was moving.
What is Hubble's Law and equation?
The farther a galaxy, the faster it recedes.
Equation - v = Hxd
T = 1/H age of universe, reciprocal of H -> age of the universe
How old is the universe according to Hubble?
14 billion years
Where in the Milky Way is the Sun located?
How many freezings did the universe experience?
10^-10 what happened?
Particle accelerators - strong, weak, gravity and electromagnetism
What is dark matter and how much of the universe if made up of it?
25% cannot see
What is Dark energy and how much of the universe is made up of it?
Pushing the galaxies apart - 70% of mass