8th grade unit 1 vocab

3. Energy cannot be created out of nothing, nor can it be completely destroyed. Energy can only change its form.
5. a large circular mass that revolves around a star
7. a force that exists between any two objects that have mass
9. an object's mass divided by its volume; a measure of how many particles are packed together into a certain amount of space
12. to use a tool to learn more about the volume, length or weight of an object
13. a small object made of rock or metal that orbits the sun
16. the circular path of an object as it revolves around another object
18. an element that makes up about 21% of Earth's atmosphere
19. distance traveled per unit of time
20. the energy an object has due to its motion
21. a streak of light in the sky that forms when a piece of rock from space burns up in Earth's atmosphere.
23. a pull or push that is applied to an object

1. an item against which the motion of an object can be measured
2. a change in the velocity (speed, direction, or both) of a body
4. the force of gravity on an object
5. the amount of energy that is stored in an object; energy that an object has because of its position relative to other objects
6. a large, circular pit in the surface of a planet or other body in space usually formed when two bodies in space collide
8. a change in the position of an object compared to another object
10. a reaction force that pushes an object forward
11. the chemical element consisting of one proton and one electron
13. the layers of gasses that surround a planet
14. size of ground movement caused by seismic waves due to energy released
15. the amount of matter in an object
17. the speed and direction of moving objects
22. a body of ice and dust that travels in a long narrow orbit around the sun