Book+3+1.1

I. What are waves? A. Periodic motion- any motion that repeats itself at regular intervals. B. Wave- a disturbance that transfers energy from place to place. i. energy- ability to do work. ii. medium- a material through which waves travel a.) gases- air b.) liquids- water c.) solids - rope iii. mechanical waves- waves that require a medium through which to travel iv. electromagnetic waves- waves that can travel without a medium v. waves that travel thru a medium and DO NOT carry the medium with them. a.) mediums are made of tiny particles. b.) wave enters medium, transfers energy to the medium's particles. c.) particles bump into each other passing waves of energy along. vii. mechanical waves are produced when a source of energy causes a medium to vibrate 3. Longitudinal waves- move the medium parallel to the direction in which the waves travels. i. spring toy- slinky dog a.) coils in the spring move back and forth parallel to the wave motion. ii. compressions - part where coils are close together a.) particles are pushed together b.) like crests iii. rarefactions - parts where coils are spread out or rarified. vii. Vibration - repeated back and forth or up and down motion. C. Types of mechanical Waves. 1. Classified on how they move 2. Transverse waves- waves that move the medium at right angles to the direction in which the waves travel. i. "across" ii. particles of the medium move across the direction of the wave. iii. highest point- crest iv. lowest point- trough a.) in between compressions b.) particles are spread out. c.) like troughs iv. Sound waves v. Compressions and rarefactions travel along spring toy, each coil moves back and forth then back. Energy travels from 1 end to another creating wave. As wave passes each coil returns to starting position. 4. Representing waves i. horizontal line - position of "rope" before disturbed ii. rest position iii. wave passes - it goes above or below rest position.


 * Quiz**

1. Waves are produced when a source of energy causes a medium to vibrate. 2. Coils of spring are close together at compressions and spread out at rarefactions. 3. crest 4. trough 5. rope 6. movement of the hand holding the rope 7. the wave needs a medium to travel through 8. transverse waves 9. transverse waves 10. longitudinal waves


 * Study Guide**

11. mechanical 12. crests 16. F- energy 18. F- surfaces 24. The crests of a transverse wave are like compressions in a wave moving through a spring toy and the troughs of a transverse wave are like rarefactions.