Understanding Waves and Wave Interactions

1. Chapter 10 Notes Waves

2. Waves carry energy & information • The information carried could be: • Sound • Color • Pictures • Radio waves – tv • Microwave – cell phones • WAVES DO NOT CARRY THE MEDIUM!!! (Ex: water)

3. Transverse Waves • Energy moves left to right • Wave moves up & down • Ex: water waves • A Rope that is moved up and down • Light • Wave and energy move perpendicular to each other.

4. Longitudinal Waves Also called Compressional Waves • Wave and energy are in same direction • Ex: Slinky • The compression will move along the slinky forward and then back. • Sound

5. Parts Of A Transverse Wave • Crests: high point of the wave • Troughs: low point of the wave

6. Wavelength ( ): • The length of one complete cycle of a wave. • From crest to crest or trough to trough.

7. Amplitude • How big or little the wave is. • Tells you how much energy the wave has. • The bigger the wave, the more energy it has.

8. Parts of a Longitudinal Wave • Compression-The condensed portion • Rarefaction-The separated part of the wave. • Wavelength-distance from compression to compression

9. Frequency • How many waves pass in 1 sec. • A wave carries its frequency to every area that it reaches • Measured in hertz (Hz)

10. Speed of a Wave • How fast the wave can transfer energy. • v = f x  • v = speed (velocity) Units=m/s • f = frequency Units=Hz •  = wavelength Units=m

11. TRANSVERSE WAVES!!!! • All travel at the same speed • The difference is in the frequency and the wavelength. If one goes up, the other goes down.

12. Parts of the EM Spectrum • Radio Waves-Longest wavelength, lowest energy, lowest frequency. • Used for TV’s, Radios and Cell Phones

13. Microwaves • A form of radio waves-some books place them separately and some put them in with radio. • They are the highest frequency (most energy) of the radio waves.

14. Infrared (IR) • Heat • Used to find people in the woods. • Infrared film detects how hot something is. • Use to detect cancer • Beneath red

15. Visible Light • ROY G. BIV-colors of visible light. • Sunlight emits UV along with other rays. • Gives us Vitamin D • Too much harmful. • Most filtered by ozone. • Red is longest

16. Main source is sunlight Helps your body produce vitamin D Overexposure = burns and skin cancer Sunscreen helps to block Beyond violet ultraviolet

17. X-rays and Gamma Rays • X-rays-See bones. • High Energy • Use lead to block! • Gamma rays-highest energy • Use to treat cancer • Generated by radioactive atoms

18. Wave Interactions • Interaction -Wave run into other object or another wave • Interaction can increase or decrease wave energy • Interaction can change the properties of the wave • Interaction can change the direction

19. A wave bouncing off of a surface Mirror Wave hitting a wall Incident wave – moving to surface Reflected wave – moving away from surface Reflection

20. Bending of wave as it changes speed Speed changes from on medium to another Air to water Water to oil Refraction

21. Bending of a wave when it comes into contact with the edge of another object Light bending around a door Diffraction

22. Interference The effect of 2 or more waves interacting Can be constructive or destructive

23. Wave crest come together at the same location Waves join together to make a larger wave Constructive Interference

24. The crest of one wave meets the trough of another wave Crest and trough subtract from each other to make a smaller wave Sometimes the interference cancels both waves Destructive Interference

25. Sound Change in frequency and pitch of a sound that is caused by either the movement of the source or the listener Ambulance Race car Doppler Effect