Fisica

Physics

I. Vocabulary
1. Planet- a celestial body that orbits the sun, is round because of it’s own gravity, and has cleared the neighborhood around it’s orbital path
2. Solar system- the sun and all of the planets and other bodies that travel around it
3. Satellite- a natural or artificial body that revolves around a celestial body that is greater in mass
4. Phase- thechange in the illuminated area of one celestial body as seen from another celestial body; phases of the moon are caused by the positions of Earth, the sun, and the moon
5. Eclipse- an event an event in which the shadow of one celestial body falls on another
6. Terrestrial planet- one of the highly dense planets nearest to the sun; Mercury, Venus, Earth, and Mars
7. Hydrosphere- the portionof the Earth that is water
8. Asteroid- a small, rocky object that orbits the sun; most asteroids are located in a band between the orbits of Mars and Jupiter
9. Dwarf planet- a celestial body that orbits the sun, is round because of it’s own gravity, but has not cleared it’s orbital path
10. Gas giant- a planet that has deep, massive atmosphere, such as Jupiter, Saturn, Uranus, orNeptune
11. Nebular Hypothesis- a model for the formation of the solar system in which the sun and planets condense from a cloud (or nebula) of gas and dust
12. Nebula- a large cloud of dust and gas in interstellar space; a region in space where stars are born
13. Comet- a small body of ice, rock, and cosmic dust that follows an elliptical orbit and that gives off gas and dust in form ofa tail as it passes close to the sun
14. Exoplanet- a planetlike body that orbits a star other than the sun
15. Perihelion - the point in the path of a celestial body that is nearest to the Sun
16. Aphelion- the furthest point from the Sun
17. Umbras- well defined if they are produced by big and far sources of light or by small and close sources of light
18. Penumbras- partialshadows, when the light is blocked but there is another source of light or when the light from the source is patially blocked

II. Section Reviews

1. Explain why objects in the sky appear to move.
* The positions of objects in the sky change over time because Earth, and everything else in the universe, is constantly moving.

2. Describe the star that’s closest to the Earth.* The Sun is the closest star to the Earth. The Sun is the brightest object in the sky because it is so close to us. The Sun is an average star. It is not particularly hot or cool and is of average size. It’s diameters is 1.4 million kilometers. The sun has a mass that is about 330,000 times the mass of Earth.

3. Describe the basic structure of the solar system.
* the sun is the mostimportant part of our system and makes up nearly 99% of the total mass of the solar system. The eight planets and their moons make up the remaining 1%. The solar system also contains many other smaller objects, such as planets, asteroids, comets, dust, and gas.

4. Explain how gravity keeps planets in orbit around the sun.
* The gravity of the sun keeps the planets in their orbits. Theystay in their orbits because there is no other force in the solar system, which can stop them.

5. Explain what happens in a lunar eclipse and what phase the moon is in during a lunar eclipse.
* A lunar eclipse occurs when the Moon passes directly behind the Earth into its umbra (shadow). The moon is in the phase of a full moon.

6. State the moon’s role in the formation of tides.* The moon’s gravitational pull is the strongest on the side of Earth nearest the moon. On this side, the ocean is pulled toward the moon, so a slight bulge is created. The solid Earth also moves slightly under the moon’s gravity, but the movement of water is more noticeable because it is water.

7. List ways in which the 4 terrestrial planets are similar to one another.
* The four...