| A | B |
|---|
| ASTRONOMY | The study of the moon, stars, and the objects in space. |
| ROTATION | The spinning motion of a planet about its axis. |
| REVOLUTION | The movement of an object around another object. |
| ORBIT | The path of an object as it revolves around another object in space. |
| PHASE | One of the different shapes of the moon as seen from Earth. |
| ECLIPSE | The partial or total blocking of one object by another. |
| SOLAR ECLIPSE | The blocking of sunlight to Earth that occurs when the moon is between the sun and Earth. |
| LUNAR ECLIPSE | The blocking of sunlight to the moon that occurs when Earth is directly between the sun and moon. |
| TIDE | The daily rise and fall of Earth's waters on shores. |
| GRAVITY | The attractive force between two objects; its magnitude depends on their masses and the distance between them. |
| LAW OF UNIVERSAL GRAVITATION | The law that states all objects attract all other objects. |
| MASS | The amount of matter in an object. |
| INERTIA | The tendency of an object to resist a change in motion. |
| WEIGHT | The pull of gravity on an object. |
| SPRING TIDE | The tide with the greatest differences between high and low tide. It occurs during a full or new moon. |
| NEAP TIDE | The tide with the least difference between the high and low tide. It occurs during a first or third quarter moon. |
