2. Physics Vocabulary

3. force a push or pull that causes an object to move, stop, or change direction a push or pull that causes an object to move, stop, or change direction

4. friction a force that slows or stops motion when two surfaces rub against each other

5. magnetism the attraction of an object containing iron to a magnet

6. gravitation the force that pulls all objects in the universe toward one another the force that pulls all objects in the universe toward one another

7. balanced forces forces acting on an object that are equal in size and opposite in direction, canceling each other out

8. unbalanced forces forces that are not equal; when one force is greater than its opposite force, the object’s motion changes forces that are not equal; when one force is greater than its opposite force, the object’s motion changes

9. energy  the ability to cause change in position or temperature

10. electric current  the constant flow of electrons from through a conductor

11. conductor  a material that conducts electricity easily

12. electric circuit  the path along which electricity can flow

13. insulator  a material that does not carry electricity

14. resistor  a material that resists the flow of electricity in some way

15. electromagnet  a temporary magnet made by passing electric current through a wire coiled around an iron bar

16. reflection  the light energy that bounces off objects

17. refraction  the bending of light rays when they pass through a substance

18. lens  a piece of clear material that bends, or refracts, light rays passing through it

19. temperature  the average kinetic energy of all the molecules in an object

20. Heat energy  the energy of moving particles in a substance

21. hydroelectric energy  electricity generated from the force of moving water

22. tidal energy  a form of hydroelectric energy that produces electricity from the rising and falling of tides

23. nuclear energy  the energy released when the nucleus of an atom is split apart

24. geothermal energy  heat from inside the Earth

25. solar energy  the energy of sunlight