RIGHT PAGE 42 October 11, 2012 Focus: Intro to Light Objective: I will be able to explain how light waves interacts with materials and analyze the eye / sight. EQ: How does scattering of light affect us? HW: project, ask someone you know the questions Warm-Up: Preview (answer these questions) Why is the sky blue? Why are clouds white?

RIGHT PAGE 42 October 11, 2012 Focus: Intro to Light Objective: 6.P.1.2 I will be able to explain how light is a form of energy and travels in transverse waves. HW: write 5 test questions about waves and light, assessment tomorrow, parent sign, test corrections Warm-Up: Read text pages C9 – C14 Write a summary / gist of what you read

Waves are started by a force. Let’s look at a slinky. When you shake a slinky, it creates a wave. In this case, we created a force by moving the slinky. Waves move away from the force. Force Direction of the wave

When a force creates a wave, energy moves not matter. The force makes the atoms in the matter vibrate. The vibration causes them to bump into each other like dominoes, sending the wave down the line. But the matter itself stays in the same spot.

Transverse Waves: In a transverse wave the matter in the wave moves up and down at a right angle (perpendicular) to the direction of the wave The wave is moving away from the force. The energy is moving up and down, perpendicular to the wave’s direction.

Which direction is the energy in the wave going? [ (away from the moving hand) / (toward the moving hand) ] How can you tell? _______________________________________________________ What is the medium for this wave? __________________________________________ Which direction is the medium moving?_______________________________________ What type of wave is this? _________________________________________________ SHOW WHAT YOU KNOW:

What is the second kind of mechanical wave? Longitudinal Waves (Compression Waves) In a longitudinal wave the matter in the wave moves back and forth parallel to the direction of the wave

The energy moves in the same direction as the wave.

Which direction is the energy in the wave going? [ (away from the moving hand) / (toward the moving hand) ] How can you tell? _______________________________________________________ What is the medium for this wave? __________________________________________ Which direction is the medium moving?_______________________________________ What type of wave is this? _________________________________________________ Compared to the direction of the energy, the medium moved in what direction? __________________________________________________________ SHOW WHAT YOU KNOW:

Which wave travels faster? Think-Pair-Share: Think about the slinky Let’s find out! –Human wave activity Since the energy is traveling the fastest way it can (in a straight line), the longitudinal wave is faster than the transverse wave. It gets from the force to the stopping point first. It is the first wave you feel in an earthquake. The transverse wave takes more time and energy to go perpendicular to the direction of the wave. You feel this wave second in an earthquake. It is sometimes called the “aftershock”.

All about ?! What do these things have in common? They all use light waves!

This is our boy, Roy. Roy’s full name is Roy G. Biv. He’s got three younger brothers: Radio, Micro and Infrared. He has to make money for his family.

Roy’s Brothers

At the end of today: You will be able to answer this question: 1.Label the electromagnetic spectrum below with the missing wave names. 2.Which wave has more energy – visible light or gamma rays?

Cornell Notes What is light? Why is a light a form of energy? energy waves. A type of energy that transfers waves. the ability to cause change. abilitychange Light is a form of energy because it has the ability to cause change. Energy is the ability to cause change.

Cornell Notes What are Electromagnetic Waves? Can all light be seen? Who is ROY G. BIV? Electromagnetic light All light travels in the form of Electromagnetic Waves. Electromagnetic waves are light waves. eyes visible light NO! We can only see some light with our eyes. This is called visible light. colors ROY G. BIV is an easy what to remember the colors in visible light!

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Electromagnetic Spectrum

A Prism breaks up visible light!

. light energy travels in waves, too. What makes one kind of light different from others is its wavelength - or range of wavelengths. Visible light includes the wavelengths our eyes can see. The longest wavelengths we can see look red to us. The shortest wavelengths we can see look blue or violet

Electromagnetic Spectrum

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 Another important thing to know about light is that it travels in a straight line unless something gets in the way to  reflect it (like a mirror)  Refract it, bend it (like a prism)  or scatter it (like molecules of the gases in the atmosphere)

Your Turn Teach your partner about Electromagnetic Waves! Tell them about: Electromagnetic Waves The different light waves in the Electromagnetic Spectrum ROY G. BIV

Quiz Your Partner! 1.Which wave has more energy – Gamma Rays or X-Rays? 2.Which wave has less energy – Radio Waves or Microwaves? 3.Which wave has a higher frequency – Ultraviolet Light or Infrared Light? 4.Which wave has a lower frequency – Visible Light or Gamma Rays? 5.Which color has a lower frequency – Red or Yellow?

Exit Ticket 1.Label the electromagnetic spectrum below with the missing wave names. 2.Which wave has more energy – visible light or gamma rays?