1. Do Now : Jan 25, 2019 1. Why is heat a form of kinetic energy? 2. What role do convection play as you heat a pot of water? Explain. 3. How can you tell whether an aluminum pan conduct heat? 4. During a cold, wet, winter, a crack in the sidewalk gets much larger. Explain why. Topic: The electromagnetic Spectrum Learning Objective: Students will be able to identify waves in the electromagnetic spectrum. Science Standard: PS 4.4a Different forms of electromagnetic energy have different wavelengths. Home Work: Study-test next Monday/Tuesday

2. Answers to do now 1. Why is heat a form of kinetic energy? Heat moves from warmer objects to cooler ones. 2. What role do convection currents play as you heat a pot of water? Explain. 1. convection currents transfer heat through the water. 2. convection moves warmed water away from the heat source and cooler water toward the heat source.

3. Answers to Do Now Cont’d 3.How can you tell whether an aluminum pan conduct heat? Put water in a pan, and place it on a burner. Turn on the burner. If the water becomes warm, the pan conducts heat. 4. During a cold, wet, winter, a crack in the sidewalk gets much larger. Explain why. Rain water seeps into the crack and freezes there. As the water freezes, it turns to ice and expands. The ice pushes against the edges of the crack. The crack becomes larger.

4. Vocabulary Electromagnetic Spectrum Visible Spectrum Refraction Reflection

5. Electromagnetic Waves Transverse waves that have electrical magnetic properties. Travel as vibrations in electrical and magnetic fields The energy transferred by electromagnetic waves is electromagnetic radiation

6. Electromagnetic Spectrum Consists of a range of energy forms that vary in wavelengths. The entire range of visible and invisible light. The diagram below shows the relative wavelengths for several types of electromagnetic energy.

7. Turn and Talk Turn to your shoulder/elbow partner and discuss why gamma rays are considered the most dangerous waves.

8. What is Light? Light has many properties of waves But light can also act as though it is a stream of particles.

9. Visible Light The part of the electromagnetic spectrum that the human eye can see.

10. Types of Waves in the Electromagnetic Spectrum The diagram below shows the relative wavelengths for several types of electromagnetic energy. Stop 606

11. Electromagnetic Energy cont’d The different forms of electromagnetic energies have different wavelengths. The shorter the wavelength, the greater the energy carried by the wave. Electromagnetic energy is considered a form of kinetic energy because it can travel as fast as 300, 000 kilometers per second in a vacuum. Light travels slightly slower through materials, such a glass or water.

12. White Light Light that looks white, is a blend of many colors. Each color has a different wavelength. Prism: a transparent solid body, often having triangular bases, used for dispersing light into a spectrum or for reflecting rays of light. Stop 607

13. Question What accounts for the fact that a rainbow is red, orange, yellow, blue and violet? A rainbow is made of white light refracted into all the colors of the spectrum. Stop 605

14. Four things can happen when light strikes an object. 1. Refraction 2. Reflection 3. Absorption 4. Transmission

15. Refraction The bending of light Light bens, or refracts when it passes from one medium to another. Can cause under water objects such as fish, to appear closer to the viewer than they really are.

16. Reflection The bouncing back of light, after striking a surface.

17. Turn and Talk! ( State test question) Turn to your shoulder/elbow partner and discuss the diagram on the right which shows a pencil in a glass of water. When viewed from the side, the pencil appears to be broken. Explain What the process that causes this to happen?

18. Essential Question----Turn and Talk Red light has a longer wavelength than blue light. How does the wavelength of light affect the degree to which it is refracted? Longer wavelengths of light are refracted less than shorter wavelengths.

19. Essential question (State test question) Which statement best describes the property of light waves illustrated in the diagram below? Give a reason to support your answer. a. Some materials absorb light waves. b. Some materials reflect light waves. c. Light waves are refracted by some materials. d. Light waves are emitted by some materials.

20. Review/Analysis Questions: 1.What are 4 things that can happen when light strikes an object? 2.Explain the difference between refraction and reflection 3.Describe the parts of the electromagnetic spectrum. 4.If visible light is made up of different color wavelengths, why does it look white? 5.What accounts for the fact that a rainbow is red, orange, yellow, green blue and violet? 6.Why are raindrops able to reflect light? Complete the Exit Ticket