1. Slinky Activity
With a partner, each person holds the slinky firmly (Don’t let go!!)
One person shake the slinky back and forth (like a Transverse wave) trying to form the waves to the right.
Document how much energy it took to form each wave.
Questions
A- What did you have to do to make more waves appear?
B- What do these waves represent?
C- Compare your effort to the number of waves seen.

2. Wave Properties 1. Waves are oscillations and they transport energy.
The energy of a wave is proportional to its frequency.
Fast oscillation = high frequency = high energy
Slow oscillation = low frequency = low energy

3. Wave Amplitude 2. The amplitude is a measure of the wave intensity.
SOUND: amplitude corresponds to loudness.
LIGHT: amplitude corresponds to brightness.

4. 3. What is the Wavelength?
Measure from any identical two successive points
(nm) 5 10 15 20 25 30 35 40

5. What is the Wave length?
Measure from any identical two successive points
(nm) 5 10 15 20 25 30 35 40
30nm – 10nm = 20nm

6. What is the Wave length?
Measure from any identical two successive points
There are 4 complete oscillations depicted here
ONE WAVE = 1 COMPLETE OSCILLATION
(nm) 5 10 15 20 25 30 35 40
22.5nm - 2.5nm = 20nm

7. Frequency
4. Frequency = number of WAVES passing a stationary point per second (Hertz)

8. Frequency and Period
5. Period (T) = length of time for one oscillation
T = 1/f f = 1/T

9. v =λf = (0.25m)(3 Hz) v = 0.75 m/s Wave Speed
6. Wave speed depends on the wavelength and frequency.
Formula: v = l f
One end of a rope is vibrated to produce a wave with a wavelength of 0.25 meters. The frequency of the wave is 3 Hertz. What is the speed of the wave?
v =λf = (0.25m)(3 Hz)
v = 0.75 m/s

10. 7. The relationship between frequency and wavelength:
Frequency increases
Energy increases
Wavelength decreases

11. 8. Behavior of Waves
-Reflection occurs when a wave bounces off a surface that it cannot pass through. A reflected wave has a smaller amplitude than the original wave because some energy is lost during reflection.

12. 8. Behavior of Waves
-Refraction occurs when a wave enters a meduim at an angle and one side of the waves moves more slowly than the other side.

13. 8. Behavior of Waves
-Diffraction occurs when a wave bends around an obstacle or passes through an opening.

14. 8. Behavior of Waves
-Interference occurs when two or more waves overlap and combine.

15. 9.Constructive Interference
Waves combine without any phase difference
When they oscillate together (“in phase”)
Crest meets Crest

16. Wave Addition
Amplitude ~ Intensity

17. 10. Destructive Interference
Waves combine and oscillate “out-of-phase”

18. Constructive and Destructive Interference

19. Wave Subtraction

20. 11. Complete the wave speed worksheet individually!