1. Waves, Sound and Light

2. WHAT ARE WAVES? A wave is a disturbance that transfers energy (not matter) from place to place. People jump up and down, moving “the wave” around a stadium. None of the individual people the stadium are carried around with the wave as it travels - they all remain at their seats.

3. ELECTROMAGNETIC WAVES Waves that DO NOT require a medium (matter) through which to travel are called electromagnetic waves. These waves can travel through empty space – like sunlight.

4. ELECTROMAGNETIC SPECTRUM All electromagnetic waves travel at the same speed, but have different wavelengths and different frequencies.

5. MECHANICAL WAVES Waves that DO require a medium (matter) through which to travel are called mechanical waves. These waves start with a vibration, and the medium’s molecules bump into each other –passing energy without moving the medium.

6. Transverse Wave String can be displaced up and down as a wave travels from left to right, but the string itself does not experience any net motion. In a transverse wave the particle displacement is perpendicular to the direction of the energy transfer.

7. Longitudinal Wave As a sound wave passes through matter, the particles in the matter oscillate back and forth, but it is the disturbance which travels, not the individual particles in the medium. In a longitudinal wave the particle displacement is parallel to the direction of the energy transfer.

8. Water Wave Water waves are an example of waves that involve a combination of both longitudinal and transverse motions. As a wave travels through the waver, the particles travel in clockwise circles. The radius of the circles decreases as the depth into the water increases.

9. SPEED OF WAVES The speed of all electromagnetic waves (including light) is 300,000 km/sec (670,000,000+ mi/hr). The speed of sound waves depends on whether the medium is a solid, liquid or gas, and whether the medium is elastic, dense or warm. In general, the speed of sound is said to be 343 m/s (768 mi/hr) in 68⁰ air.

10. THE COLOR OF OBJECTS When a light wave strikes an object, the light can be reflected, transmitted, or absorbed. When combined in equal amounts, the three primary colors of light (RGB) make white light. ROYGBIV - Light and Color