What do these images have in common?

1. What do these images have in common?

2. They are all WAVES!!!Time for Surfing!!! Why Waves Are Wonderful!!

3. Imagine that your family has just returned home from a day at the beach. You had fun playing in the ocean under a hot sun. You put some cold pizza in the microwave for dinner, and you turn on the radio. Just then, the phone rings. It's your friend calling to ask about homework.

4. Unit 4The Nature of Waves

5. Unit Goals What are the major parts of a standard wave? What are the different types of wave? How do waves travel? How are waves pertinent to my everyday life?

6. What Is A Wave? A TRANSFER OF ENERGY through matter OR empty space A MEDIUM is any material that a wave travels through. A medium can be a solid, liquid or gas.

7. Waves and Work As a wave is traveling it is moving everything else in its path (waves working). Anything floating on the surface of water is being worked by waves. Example: Boats and ducks bob up and down on a waves shows that waves are transferring energy.

8. Can anyone describe the energy transfers that are occurring here? MovingObject Wavesshow transfer of energy from propeller through water Medium=Water

9. Medium A MEDIUM is any material that a wave travels through. A medium can be a solid, liquid or gas. A medium can be a solid, liquid or gas. The plural ( more than one) of medium is media

10. There are Two Major Categories of Waves Mechanical Electromagnetic

11. Mechanical Waves Need a medium to transfer energy! CANNOT travel through empty space OCEAN WAVES AND SOUND WAVES ARE EXAMPLES

12. Electromagnetic Waves Do not need a medium, CAN travel through empty space! Electromagnetic waves (light waves, microwaves, x-rays) can travel through empty space

13. Types of Waves • There are three type of waves: • Transverse • Longitudinal • Surface/Water

14. Transverse Wave Transverse waves- are particles that move in an up –and- down motion. The particles in a transverse wave move across or perpendicular The highest point on a transverse wave is called a Crest The lowest point on a transverse wave is called a Trough

15. Transverse Wave

16. Longitudinal Waves Longitudinal waves- particles of the medium vibrate back and forth along the path the wave moves. Compression- the part of the longitudinal wave where the particles are crowded together Rarefactions- where the particles are spread apart

17. Time to Practice! • Use your JUMP ROPE!To demonstrate a transverse wave: • Work with a partner • One of you move your end of the Ropeback and forth (left and right, like a snake crawling), perpendicular to its stretched length. • The other student must hold his or her end of the Rope still • A series of transverse waves will be generated and will travel through a medium (Rope)

18. Longitudinal Waves

19. Longitudinal Waves A sound wave is a longitudinal wave. Sound waves travel by compressions and rarefactions of air particles

20. Time to Practice! • Use your Slinky to demonstrate a longitudinal wave: • Work with a partner • Stretch it out along the table • One of you grasp and draw several coils of a stretched Slinky toward yourself • Release the coils • The other student must hold his or her end of the Slinky still • A longitudinal wave pulse will be generated and travel down the length of the Slinky (Medium)

21. Surface and Combination Waves Combination waves- when a transverse wave and a longitudinal wave combine to form a surface wave. Surface waves look like transverse waves, but the particles of the medium move in circles rather than up and down.

22. Properties of Waves

23. A. Rest Position: The center of a wave; point where particles stay without disturbance

24. THERE ARE 4 BASIC PROPERTIES OF WAVES! 1) AMPLITUDE 2) WAVELENGTH 3) FREQUENCY 4) SPEED

25. Amplitude: The farthest distance the particles of a wave’s medium vibrate from their rest position; BIGGER=more energy

26. Wavelength: The length of the wave; crest to crest or trough to trough; compression to compression; rarefaction to rarefaction; smaller=more energy

27. Frequency: The number of waves produced in a given amount of time

28. Lets Make a Model! • In you engineering notebook 2) On the top half of the page, use some yarn to make a transverse wave. Neatly label the crest and the trough! 3) On the bottom half of the page, make a longitudinal wave. Neatly label the compression and the rarefactions

29. Wave Speed Speed at which a wave travels Wavelength x frequency = wave speed

30. Let’s Try! Wavelength – 10 cm Frequency – 20 Hz Wavelength – 2 cm Frequency 4000 Hz A wave has a wavelength of 5 cm. Its frequency is 700 Hz. What is its wave speed?

31. Let’s Review!!!!

32. Wavelength Crest to Crest Trough to Trough Make a LARGE wavelength! Make a small wavelength! Which had more energy????

33. Amplitude Small amplitude and big wavelength HUGE amplitude and small wavelength Which would sound louder? Bigger amplitude – more energy!!

34. Amplitude and Wavelength to our EARS

35. Frequency • Number of waves produced in a given amount of time • Measured in HERTZ (waves/second) • Higher frequency = more energy • PITCH related to frequency! • Higher pitch – higher frequency – more energy!

37. Exit Ticket – On ENB Rest Position Draw a transverse wave with 5 full waves. Identify: *Amplitude *Wavelength *Crest *Trough