Energy

1. Energy Pg. 284-317

2. Energy, What is it? • Definition: Capacity of a system to do work. • What is a system? • What is capacity? • What is work? Work is done when a force moves an object (force x distance)

3. What does energy do? • Energy can cause motion or cause changes in matter. • Examples:

4. Law of Conservation of Energy • Energy cannot be created or destroyed, only changed from one form to another.

5. Potential Energy • Potential energy (PE) is energy that is stored. • Examples: (draw a picture)

6. Kinetic energy • Kinetic energy(KE) is the energy of motion. • You cannot have KE without PE. • Examples

7. PE can change into KE • Write or draw three ways energy can change from one form to another. Energy Video Clip

8. Solar Energy • What are the effects of the sun on the Earth? • 1. Sun’s energy evaporates water to form clouds which produces rain, sleet, snow, and hail. • 2. Sun’s energy heats the Earth’s surface. • 3. Plants use solar energy to make food. (photosynthesis) • 4. Chemical energy in fuels comes from the sun (0il).

9. Heat Energy • Energy of moving particles is heat energy. • Source of heat Energy • 1. Burning (chemical reactions) • 2. Friction (rubbing hands together) • 3. Electrical energy(toaster)

10. Temperature • Average KE of the particles in a substance. • Materials heat up differently due to their atomic structure.

11. Types of heat transfer • 1. Conduction: Transfer heat by touching.

12. Convection Convection: Faster particles rise, slower particles sink. Faster particles less dense. Slower particles more dense

13. What makes the wind blow? • Uneven surface heating of the Earth’s surface causes air to rise and cool air to sink. • Warm air rising is replaced by sinking air. This makes it windy!

14. Radiation • Heat energy moves through space by radiation. • Heat transfers without touching

15. Electricity • Form of energy that is produced when electrons move from one place to another. • Movement of charged particles produces electricity.

16. Electricity • These forces of attraction and repulsion make electrons move away from areas with a negative charge and toward areas with a positive charge.

17. Static Electricity • Build up of electric charges in an object. • What happens when a balloon is rubbed on hair? • How does lightning form? • How are these both similar events?

19. Current Electricity • Definition: Constant flow of electrons. • current is measured in amps

20. Batteries • Batteries “push” electrons through wires. • The push is the volts of the battery. • The more energy the electrons carry the more work that you can do.

21. Conductors and insulators • Metal and pure water are good conductors of electricity. • Rubber, plastic, and clothing are good insulators of electricity • Picture pg. 299

22. Magnetism • Magnetism is a force that pulls across a distance. • All magnets have two poles. • Magnets produce a magnetic field. The field is the strongest at the poles. Energy Video Part 2

23. Light • Light is a form of energy that travels in waves. • Light travels outward in all directions from a source. • Light always travels in a straight line.

24. Speed of light • Light travels through a vacuum at 186,000 mi. per sec. or 300,000 km/sec. • Nothing goes faster than light • Light can travel slightly slower through matter (water, air, glass).

25. Light Waves • Light is really waves. All waves carry energy! • The waves are in a group called the electromagnetic spectrum.

26. Invisible Waves • Radio waves, microwaves, Infrared waves (heat), Ultraviolet (sunburn), x-rays, and gamma rays are all invisible to our eyes.

27. Visible Light • All the colors of the rainbow • ROYGBIV • Our eyes see light green the best.

28. Waves • We can draw a picture of a wave and identify parts.

29. Why we see rainbows • Light refracts (bends) as it goes through water droplets in the sky. • When light bends we are able to see ROYGBIV in the sunlight.

30. Colors • We can only see what wavelengths are reflected to our eyes. • All other wavelengths are absorbed into the material. • Why do you get hotter wearing a black shirt on a hot day?

31. Sound Energy • Form of energy produced by vibrating objects. • Sound moves similarly to the way water will boil. The air molecules bump into other air molecules and transfer the energy. • The energy moves through the air.

32. How we hear. • Vibrating air particles will hit the person’s eardrums and make them vibrate. These vibrations will be passed along to nerves that lead to your brain. • Soundwave animation • Guitar string soundwaves

33. Pitch • High pitched sounds have waves that are close together and are at a high frequency. • Low pitched sounds have waves that are farther apart and at a low frequency. • Range of our hearing • Wave form generator

34. Energy wrap up • Energy video part 3

35. Flashlight • What energy transfers happen in a flashlight?

36. Toaster

37. Cellphone

38. Car Stereo speakers

39. Bonfire

40. Hydroelectric Dam

41. Car

42. You

43. Journal Quick write • How does this hot air balloon go up? (use vocabulary)

44. Quick write • Explain how a flashlight will gradually lose it’s brightness. • Use these key words • Electrons • Energy • Chemical energy • Positive and negative

45. Quickwrite • Identify and explain the types of heat transfer seen in this picture.