1. Energy Chapter 14

2. Prior Knowledge What is energy? What are waves and where are they found? What are the parts of a wave? What is light?

3. 14-1 What Are Some Forms of Energy? 1. Energy= the ability to cause change in matter. 2. Potential energy= energy that is due to the position or condition of an object.  Example: Skier at top of hill. Yo Yo before it falls Newton ball before it is let go. Water at top of waterfall Stretched rubber band Drawing a bow and arrow

4. 3. Kinetic energy = Energy of motion. Examples: Skier moving down a hill yo yo moving up and down. Newton balls moving back and forth Water flowing down a waterfall Rubberband flying through the air Arrow moving towards a target

5. Examples of Energy Transformations 1. Fireworks: -starts as stored chemical energy as a rocket -moves to kinetic energy at the rocket moves into sky. -Flash of light is chemical energy - Sound (bang) is sound energy. 2. Battery: -starts as chemical potential energy. - When battery is being used it is electrical energy. - Heat is produced so it is thermal energy. -Light shown is light energy.

6. 14-2 What are Waves? 1. Waves are a disturbance that carries energy through matter or space.

7. 2. Wavelength = distance from middle of crest to middle of next crest on a wave. 3. Amplitude = distance from resting position to either the top of crest or bottom of trough

8. Sound waves 1. A single sound wave is made up of one compression area and one spread area. 2. Frequency = number of times the string vibrates in a given amount of time. (hertz) 3. Pitch: refers to how high or low sound is. The higher the frequency or a wave the higher the pitch.

9. 4. Loudness is measured in decibels (dB). -The larger the amplitude the louder the sound. - Loud sounds can cause pain and hearing damage. *wear ear protection to block sounds above 80 dB. (airplanes, rock concerts, factories.)

10. Light and Electromagnetic Waves 1. Light is a form of energy that travels in waves but doesn’t need matter. 2. Electromagnetic spectrum = all energy waves that travel at the speed of light in a vacuum. - radio, microwaves, infrared, visible, ultraviolet, x- ray, and gamma rays - Visible light is part of the spectrum that you can see.

13. Light Energy from the Sun - Heat - Makes air flow - Water to evaporate (water cycle) - Produces food for plants, animals, humans

14. Photosynthesis  Light Carbon Dioxide + Water >>>>> Glucose + Oxygen Chlorophyll

15. 14-3 How Does Light Behave? 1. Reflection = The bouncing of light off a surface. - mirror or still water - rough surfaces don’t reflect light they absorb light.

16. 2. Visible light is white. - when white light passes through a prism, its path changes, and white light is separated. **Red Orange Yellow Green Blue Indigo Violet  Carrot is orange because all other colors are absorbed and orange is reflected.  Black objects absorb all wavelengths of light and reflect very little light. This is why black top parking lots are hot.

17. Refraction and Diffraction 3. Refraction = The bending of light as it passes from one material to another. Examples: pencil, straw, or flower in glass of water. (light leaves water and enters air it speeds up and bends.)

18. 4. Diffraction = The bending of light around the edge of an object. -Particles in the air cause diffraction in the atmosphere. -Longer wavelengths (red) tend to diffract more often.

19. 5. Transparent = allowing almost all light to pass through. Example: colored glass, light covers 6. Translucent = allowing some light to pass through. Example: tissue paper, wax paper, some plastic. 7. Opaque = don’t allow any light to pass through. Example: metals, clay pots, soil, tree, house