1. Sound and Light Wave interactions

2. Four wave interactions • When a wave encounters a surface, four interactions can occur: • reflection, • refraction, • diffraction, or • absorption.

4. Sound Waves • Longitudinal waves • Sound can travel through any medium, but it cannot travel through a vacuum. There is no sound in outer space. • The speed of sound depends upon the type of medium and its state.

5. Medium and speed of sound • Sound travels fastest through solids. This is because molecules in a solid medium are much closer together than those in a liquid or gas, allowing sound waves to travel more quickly through it. In fact, sound waves travel over 17 times faster through steel than through air. The exact speed of sound in steel is 5,960 meters per second (13,332 mph). Speed of sound in air is 343 m/s and in water is 1482 m/s. Speed of sound in Diamond is

7. Light • Don’t need a medium, can travel in a vacuum • Transverse waves • Light waves travel 300,000,000 m/s. • Light can behave like a wave or like a particle • A “particle” of light is called a photon

8. The colors we see in objects are the colors that are reflected, all other colors are absorbed. A red t-shirt appears red because red is reflected to our eyes and the other colors are absorbed. • When all colors are being reflected we see white light (white isn’t really a color)

9. When all wavelengths of light are being absorbed we see black (black also, isn’t really a color)