| A | B |
|---|
| one of the four large outermost planets that is made of mostly gas | gas giant |
| a force that pulls two objects together | gravity |
| when 1/2 of the lit portion of the moon is visible on the left | last quarter (third quarter) |
| the amount of material that an object has in it | mass |
| National Aeronautics and Space Administration | NASA |
| a state of matter without definite shape or volume | gas |
| anytime of year marked by a particular change in weather | seasons |
| the sun with all the things that revolve around it | Solar System |
| the season from March 21 through June 21 | spring |
| the season from June 21 through September 23; northern hemisphere is tilted towards the sun | summer |
| the outer face of anything | surface |
| one of the four innermost planets that is made of rock (Mercury, Venus, Earth and Mars are terrestrial planets) | terrestrial planet |
| the rise and fall of the water level on earth | tides |
| 1000 meters | kilometer |
| the season from December 21 through March 21; northern hemisphere is tilted away from the sun | winter |
| when none of the lit portion of the moon is visible | new moon |
| a gas that is given off by plants and used by animals | oxygen |
| when 1/2 of the lit portion of the moon is visible on the right | first quarter |
| when all of the lit portion of the moon is visible | full moon |
| one full spin of an object around an axis | rotation |
| the layer of gasses that surrounds the earth | atmosphere |
| the Earth's axis is tilted 231/ 2 degrees toward the North Star | axial tilt |
| an imaginary line through a spinning object | axis |
| a gas in air that is taken in by plants, exhaled by animals, and given off when fuel is burned | carbon dioxide |
| the particular state of a person or thing | condition |
| a large body of matter revolving around the sun | planet |
| bouncing of a wave or ray off a surface, changing its direction | reflection |
| the movement of one object around another object | revolution |
| a straight line passing through the center of a circle and meeting at each end of the circle | diameter |
| a complete or partial hiding of the sun caused by the moon's passing between the sun and the earth | eclipse |
| the season from September 23 through December 21 | fall |
