1. Waves & Electromagnetic Spectrum Mrs. Hooks Unit 7

2. Learning Targets 07-PS4-1, 07-PS4-2, 07-PS4-3 1.I can explain how waves transport energy. 2.I can describe the properties of waves. 3.I can describe and model reflection, refraction, and diffraction of a wave transmitted or absorbed through a material. 4.I can prove that digitized signals are more reliable than analog signals.

3. Waves Wave- a repeating movement or disturbances that transfers energy through matter or space – All waves carry energy without transporting matter from place to place. – Waves are either: mechanical or Electromagnetic – All waves are produced by vibrations! http://www.youtube.com/watch?v=7yPTa8qi5X8&feature=player_detailpage Medium- matter through which a wave travels – A medium can be solid, liquid, gas or a combo of these. – Not all waves need a medium to travel…light and radio waves can travel through space.

4. Types of Waves - Mechanical Waves- waves that can travel through a medium Transverse Energy moves perpendicular or back and forth at right angles to the direction the wave travels – Ex. Ocean waves, waves through a rope, seismic waves Compressional or Longitudinal Energy in mediums moves parallel, or in the same direction that the wave travels. – Ex. Sound waves, seismic waves -Electromagnetic Waves-light, radio waves, and x rays. Contain both electric and magnetic parts that vibrate up and down.

5. Features of a Wave Transverse Transverse waves have crests- the highest point, and troughs- the lowest points of the wave Compressional or Longitudinal Compressional waves have dense regions (coils close together) called compressions and less dense regions called rarefactions Next Page- T-chart

6. Properties of Waves Wavelength- λ- distance between one point on a wave to a similar point nearest to it. (Crest to crest, trough to trough, compression to compression, rarefaction to rarefaction)

7. Properties of Waves Frequency- the number of wavelengths (cycles) that pass a fixed point each second

8. Properties of Waves Amplitude- a measure of energy in a wave, the wave strength – The more energy a wave carries  greater amplitude

9. Properties of Waves Wave Speed- Velocity- the speed of a wave is dependent upon the frequency times the size of the wavelength

10. Behavior of Waves Law of Reflection-when a wave encounters a barrier it, it will reflect at an equal angle to the incoming angle Reflection- occurs when a wave strikes an object and bounces off of it – All types of waves can be reflected (ex. Sound, water, light)

11. Behavior of Waves Refraction- change in direction of a wave when it changes speed as it travels from one material to another

12. Behavior Of Waves Diffraction- bending of waves around an object