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Short answer
| Question | Answer |
|---|---|
| After a supernova explodes, what is left behind? | a neutron star or black hole |
| What is the basis (evidence) for the belief that matter is made up of small particles in motion? | Brownian Motion |
| What standards did Fahrenheit choose for the 0 and 100 marks on his thermometers? | 0 - a mixture of ice, salt, & water 100 - his body temperature |
| Where do all the elements other than hydrogen and helium come from? Explain. | Light & middle wt. elements, up to iron, are created in stars - fusing He cuz they ran out of H. A supernova prod. all elements beyond Fe du_ the explosion, which scatters all elements so they can be condensed to form new stars & their planetary systems. |
| When stars are photographed from the orbiting Hubble space telescope, do they twinkle? | No. The twinkling effect is caused by temperature & density changes in the atmosphere. |
| What causes a star to become a red giant? | When a normal star runs low on H, it begins to fuse helium & expands to thousands of times its former size. |
| What evidence did Edwin Hubble discover that supports the Big Bang theory? | By measuring the red-shift of the light from stars, Hubble discovered that the farthest galaxies are moving away from us the fastest, thus showing that the universe is expanding. |
| What does science predict will happen to our sun in about another 4 billion years? | Become a red giant then shrink to a white dwarf then cooling to a black dwarf |
| Explain dark matter or dark matter/energy. | The motions of stars in galaxies cannot be explained by the amount of known (visible) mass, so scientists have hypothesized the existence of dark matter or dark matter/energy. |
| Global warming What is it? What caused it? How can we fix it? | - An increase in the average global temperature due to an increase in greenhouse gases - mostly the activities of man - conservation, recycling, alternative energy sources |
| Explain how Galileo's approach to physics represented an improvement over previous approaches. | Galileo believed in testing everything by controlled experiments, rather than relying on past authority. |
| Right now we are moving about 800 mi/hr due to the Earth's rotation! Why are we not aware of this motion? | We can't feel constant velocity |
| Compare Aristotle's & Galileo's ideas of the motion of earthly objects. | A - rest is natural A - motion requires continuous force A - 10 lb rock falls 10x faster than 1 lb rock G - rest & uniform motion are natural G - force changes motion G - all objects fall with the same acceleration, neglecting air friction |
| When Cape Kennedy was communicating with our astronauts on the moon, there was a minimum dely of about 2.5 seconds. Why? | Even at the speed of light, radio waves require ~2.5 sec. to travel to the moon and back. |
| Contrast the vertical and horizontal components of the motion of a thrown football. | horizontal - constant velocity vertical - constant acceleration |
| According to Aristotle, what keeps an arrow moving after it leaves the bow? | Displaced air from the front of the arrow rushing around behind the arrow to fill the vacuum. |
| In the 1700s, 90% of people in the Western world were involved in farming. What percent of people in the Western society are needed today to produce enough food for all of us? | 3-5% |
| What is the difference between scientific law and scientific theory? | Law - what always happens Theory - why something happens |
| Define accuracy | How close a measurement is to the correct value |
| Why did Mendeleev's periodic table become so popular? (2 reasons) | 1. He organized known facts in an easy-to-read format 2. He made predictions that came true |
| What is the uncertainty of measurement in experiments and how do we deal with it? | Measurements are never exact. We calculate on an average trying to get as close to accuracy & precise as possible. |
| Define precision. (2 definitions) | 1. How close a series of measurements are to each other. 2. How many significant figures are actually measured. |
| Give the names and chemical symbols of up to 5 elements whose symbols are taken from their Latin or German names. | Pb lead Sn tin K potassium Au gold Cu copper |
| Define isotopes | Isotopes have similar characteristics. They have the same atomic number (protons & electrons) but different masses (neutrons). or Atoms of the same element which have different # of neutrons in their nuclei. |
| In 25 words or less, what is science? | Science is not relying on past authorities and experiments are based on logic, observation, and controlled experiments. |
| How do we know that distant stars contain the same elements we have here on Earth? | Each element's spectra uniquely identifies it, like a fingerprint identifies a person. |
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niinimoshe
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