1. Waves and Interference Transverse & Longitudinal Waves

2. Transverse Waves A person shakes the free end of a rope up & down. The wave moves to the right. The motion of the rope is at RIGHT ANGLES to the direction in which the wave is moving. This is a transverse wave. –Eg: Strings in musical instruments, –Waves in a stadium. T

3. Longitudinal Waves Sometimes the medium and the wave move in the same direction (parallel). These are longitudinal waves. Ex: Sound waves. compression rarefaction

4. Identify the wave: Transverse wave – Spring is moved up & down Longitudinal Wave - Spring is moved in and out

5. Interferences Occur when 2 waves pass through each other. 2 types of interference: 1) Constructive Inference: 2 Crests that pass through each other make a BIGGER wave. 2) Destructive Interference: 2 Waves that pass through each other make a SMALLER wave.

6. Interference Constructive Interference Destructive Interference crest to crest adds to amplitude crest to trough reduces amplitude

7. Lab on Waves Move into groups of 4 ONLY. DO NOT TANGLE THE SLINKIES. DO NOT STRETCH the slinkies too much.

8. Debrief Part I – Longitudinal Waves In which direction do the pieces of string move as the wave moves through the slinky? Part II – Transverse Waves In which direction do the pieces of string move as the wave moves through the slinky? 2. What will happen to the frequency, period and wavelength if you shake the spring faster? Frequency – Period – Wavelength –

9. Part III - Interference Step 2 – Constructive Interference Step 3 - Destructive Interference