Light…

1. Light… One of our forms of energy (radiant)… what can we do with it… how about without it???

2. Light… it is a wave • Wave = repeating pattern • Waving good bye • Water waves • radio/tv/cell phones

3. Why don’t you draw one… • Include: wavelength, amplitude, frequency • Wavelength: length of the wave until it repeats. • units = meters

4. Frequency: how many wave lengths per second. • Units = per seconds… or Hertz (Hz) • Why don’t you figure out the frequencies below.

5. How is frequency used? • Frequency can identify any electromagnetic wave based off of how many times it repeats itself every second. • Radio stations: 98.6 FM (MHz = megahertz) • Any other signal… synchronizing remotes, wireless video game controllers, cell phones, internet • Tells us how much energy the wave has • The wavelength can also do this. • yarp

6. What about amplitude? • Intensity • Sound = volume • Bigger the speaker, the louder the sound (old school) • This allowed for more squish and stretch (back and forth movement can be seen in the speaker) • There are other ways to get more volume • light = brightness • Yarp = yarpness

7. How do waves move??? • Use a slinky if you got one around • Transverse = up and down • Ex. Electromagnetic spectrum • Longitudinal = squish and stretch • Sound • yarp

8. How waves move draw em… • Hope you got the laser, mirror, wawa and overhead ready • 1. plane waves (straight) • 2. circular waves (ripple) • 3. Reflect (bounce)

9. More??? more • 4. refraction (bend) • 5. Diffraction • (spread through an opening) • 6. Absorption • (stays in material) • 7. Transmission • (pass through)

10. Properties of color Color cool…. Sound good to…

11. Electromagnetic spectrum

12. Speed of light • All electromagnetic waves move the speed of light • 3 x 108 m/sec • Circle the earth 27 times in 1 second • It is constant… • Can “slow” it down in different materials • yarp

13. Light colors add together • Red, green, blue = 3 primary colors • All together make white… • Different intensities and combinations of each make all different colors…. • red + green = yellow • blue + green = light blue (cyan) • Red + blue = light pink/red (magenta) • Colors overlap to make new colors • yarp

14. YARP!!! screen

15. MORE OPENINGS!!! YARP!!!

16. How your eye sees light Cones for color cones for Red, green, and blue Rods for black and white

17. coolness • Cone cells for color need more light intensity • Rod cells (black and white) work well in low light intensity… • That is why at night things are less colorful and more black and white • Color blindness is because one or more of your cone cells are missing/not working • Red cone cells are common to miss • yarp

18. What animals are color blind? • Have students guess before you click!!! • Dogs • Deer • Why do you think deer hunters wear blaze orange??? • yarp

19. The development of computer screens • Old screens… green • CGA screens = 4 colors • Yellow and red OR blue and black • VGA screens = 256 color intensities for a pixel • Now… 256 color intensities for EACH COLOR • 256 Red x 256 green x 256 blue • 16,777,216 color combinations • Customizing virtual “avatars” with color bars • yarp

20. The bars look kinda like this… Move the bars up and down… Desired color Each color has 256 possibilities…

21. sound Bringing back amplitude in a big way

22. sound • Sound waves caused by vibration of materials • No material, no sound • In space no sound (outside your helmet) • A longitudinal wave (squish stretch) • yarp

23. Speed of sound • Changes for different materials • Air sea level = 344 m/sec • Air mountain top = 330 m/sec • Air hot desert = 360 m/sec • Water = 1500 m/sec • Iron = 5960 m/sec • Old string can phone • Yarp = faster than speed of light

24. More on sound… • Frequency = pitch, specific note heard • More frequent = higher pitch • Less frequent = lower pitch • Amplitude = volume • How far back and forth the speaker can physically move • yarp

25. Show amplitude with this image Plastic or paper old school Voice coil has electricity going through it to change it’s magnetic field. Moving it forward or backwards based on the magnet moving the cone to push air and make sound

26. Other cool things Coolness of waves

27. Constructive and destructive interference • How the waves line up is key. • Same frequency • Same amplitude • Jamming = destructive interference • Same yarp

28. interference • Amplification = constructive interference • Circling signal through again and again to increase the volume, intensity, etc… • yarp

29. Doppler effect • Squishing or stretching to change the frequency of a wave. • This can be done by moving the source of the signal… • Or bouncing off of moving objects to get your signal returned… speeding radar. • Check out your sweet web site… for a couple of these • yarp

30. Sound decibels • Logarithmic scale

31. What we can hear… Feeling pain Volume: you need to increase the volume to hear at the blue line Pitch… high number = high pitch

32. equilizers

33. polarization • When electromagnetic waves come in at different angles… use thin openings… • To block certain • Parts of the wave • Draw it… • Show it… • Yarp it…

34. filters • Color filters allow only certain frequencies of light to pass through… • Red filters allow red light to pass (you see it) • It absorbs the rest of the colors…. • Why don’t you show em the glow in the dark dealy….??? Maybe later? • yarp