1. 1.Define the following terms: wave, frequency, period 2.Draw a simple sine waveform and label these: amplitude, wavelength, crest, trough

2. Define the following terms: 1)Superposition 2)Constructive interference 3)Destructive interference 4)Standing wave 5)Nodes 6)Antinodes

3. The Properties of Waves 1.Reflection 2.Refraction 3.Superposition 4.Diffraction

4. Have you ever experienced having a really bad cell phone reception in the middle of an open, urban area?

5. Question: What happens when a wave meets another wave? Wave + Wave = ?

7. Superposition (Interference) Two waves can be ‘added’ together Constructive interference occurs when the two waves are in phase (i.e. crests meet crests, troughs meet troughs) Destructive interference occurs when they are 180 degrees out of phase (i.e. crests meet troughs)

9. Constructive Interference (Antinode)

10. Destructive Interference (Node)

20. Ruben’s Tube

21. Standing Wave, Nodes and Antinodes Wave produced by the superposition of two equal but opposite waves Antinodes – places where constructive interferences occur (double crest and double trough) Nodes – places where destructive interferences occur (crest + trough = zero displacement)

25. Interference Pattern Anti-nodes are formed when constructive interferences occur where two waves are in phase because the path differences are whole numbers (0, 1, 2, 3…). Nodes are formed when destructive interferences occur where two wave are 180 o out of phase because the path differences are ½, 1½, 2½, 3½…

26. Constructive Interference Destructive Interference Anti Nodes (anti nodal line) Nodes (nodal line) Crest + Crest Trough + Trough Crest + Trough In phase180 o out of phase Path differences are 0, 1, 2, 3, 4… Path differences are ½, 1½, 2½, 3½…