1. diagram

2. a plan, sketch, drawing, or outline made to show how something works or to show the way parts are put together

3. force

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

5. gravity

6. the force that pulls all things in the universe toward each other; the force that pulls things down on Earth

7. magnetism

8. a force that pulls iron or steel across a distance; a force that attracts or repels magnetic material

9. friction

10. a force that resists motion when objects rub against each other

11. motion

12. a change in the position of an object

13. Simple machine

14. a device with few or no moving parts that changes the size or direction of a force

15. energy

16. the ability to make a change in matter

17. electricity

18. energy that flows through a circuit and can create light, heat, magnetism, sound, or other effects

19. Electric circuit

20. a closed path where electricity can flow

21. electromagnet

22. a temporary magnet created when electricity passes through wire wrapped around an iron bar

23. Thermal energy

24. heat energy caused by the movement of molecules in an object

25. conduction

26. the direct transfer of heat between objects that touch

27. convection

28. heat moving from one object to another caused by mixing a liquid or a gas

29. radiation

30. the movement of thermal (heat) energy by electromagnetic waves, such as light waves from the sun

31. Sound energy

32. a change in matter made by vibrating objects

33. vibrate

34. to move back and forth

35. pitch

36. how high or low a sound is

37. Volume (in relation to sound)

38. the loudness or amount of a sound

39. conductor

40. a material that allows energy to flow through it easily

41. Insulator

42. a material that does not allow energy to flow through it easily

43. Light energy

44. a form of energy that travels in waves and can be seen with our eyes

45. reflect

46. when light rays bounce off an object

47. refract

48. when light rays bend

49. absorb

50. to take in and hold inside

51. Fossil fuels

52. materials formed from decayed remains of ancient plants and animals that are burned to produce heat; coal, oil, and natural gas

53. Solar energy

54. energy from sunlight

55. Mechanical energy

56. energy of motion

57. Potential energy

58. energy that is stored in a material because of its position or condition

59. Kinetic energy

60. energy of a material in motion