•EXAM #2 THIS FRIDAY, 10/16

•BRING PENCIL, CALCULATOR, AND SHEET OF NOTES (PUT YOUR A00 NUMBER ON IT)

•CHAPTER 4 OWL ASSIGNMENTS (& FIRST CHAPTER 6 ASSIGNMENT) DUE 10/15

Announcements

Wave Review

Amplitude

Sound = VolumeVisible Light =

Brightness

Wavelength or Frequency

Sound = PitchVisible Light = Color

The Electromagnetic Spectrum

How does electromagnetic (em) radiation affect molecules?

•Microwave

•IR

•Visible

•UV

•X-Rays

Frequency () & Wavelength ()

Electromagnetic waves in vacuum all travel at c, the “speed of light”

c= 2.998 x 108 m/secLight acts like a wave

(reflects, refracts, interferes, etc.) BUT…

c

c

c

Energy is Quantized

Light also acts like particlesPhoton= “Packet” of energyEnergy is proportional to Frequency (and )Planck’s Equation:

hEphoton

UV-B Light and DNA Damage