1. Energy in Waves

2. A Wave is… Any disturbance that transmits energy through matter or space. Energy in Waves

3. A Wave is… Waves carry energy. Any substance through which a wave can travel is called a medium. A medium can be a solid, liquid, or gas. –Ex: strings/wire, air, water.

4. Waves that require a medium are called Mechanical Waves. –Example: sound Waves that can transfer without a medium are called Electromagnetic Waves. –Example: light, microwaves, x-rays.

5. Types of Waves Waves are classified based on the direction in which the particles of the medium vibrate, compared with the direction the waves travel.

6. Types of Waves 2. Longitudinal Waves (or Compression Waves) –The particles of the medium vibrate back and forth. Ex: Sound waves

7. Longitudinal Waves Rarefaction- A section of the wave where particles are less crowded than others. Compression- a section of the wave where the particles are crowded together.

8. Types of Waves 1. Transverse waves –When the motion of the medium particles are at right angles to the motion of the wave. (The particles move across or perpendicular.) –Particles vibrate with an up-and-down motion.

9. Transverse Waves Direction of particles

10. Transverse Waves Ex: Although electromagnetic waves do not travel by vibrating particles in a medium, all electromagnetic waves are classified as transverse.

11. Wave Properties Amplitude –the maximum distance the wave vibrates from its rest position (node). –Large amplitude means more energy.

12. Wave Properties Wavelength – distance between adjacent crests. Frequency – The number of waves that pass a given point in a certain amount of time. –Measured in Hertz (Hz). –1 Hz = 1 wave/sec. –Higher frequency means higher energy.

13. Wave Speed Can be calculated by: –S = λ f (speed= wavelength x frequency) –Ex: What is the speed of a wave that has a wavelength of 2m and a frequency of 6 Hz? –Solution: S = λ f S= 2m 6 Hz S = 12 m/s