Presentation is loading. Please wait.

Presentation is loading. Please wait.

 Explain how forces cause waves.  Explain how waves transfer energy.  Classify wave types.  Compare and contrast different wave types in an experiment.

Similar presentations


Presentation on theme: " Explain how forces cause waves.  Explain how waves transfer energy.  Classify wave types.  Compare and contrast different wave types in an experiment."— Presentation transcript:

1

2  Explain how forces cause waves.  Explain how waves transfer energy.  Classify wave types.  Compare and contrast different wave types in an experiment.

3  You experience waves everyday. Every sound you hear is a sound wave, every sight you see depends on light waves!

4  A Wave is a disturbance that transfers energy from one place to another.  Waves can transfer energy over distance without moving matter the entire distance.  For example: An ocean wave can travel many kilometers without the water itself moving many kilometers.  Water moves up and down

5  Forces can start a disturbance, sending a wave through a material. Rope Wave Water Wave

6

7  A rope tied to a doorknob, water, and the ground all have something in common.  They are all materials through which waves move.  A medium is any substance that a wave moves through. Like water or a rope

8  Waves that transfer energy through matter are known as mechanical waves.  All the waves you’ve learned about so far are mechanical waves.  An Earthquake wave is a good example of energy transfer.

9

10  Waves can be classified by how they move!  Some waves transfer an up-and-down or a side-to-side motion.

11 Transverse Wave direction of disturbance direction of wave transfer of energy../Animations/wslm05_pg7_force.html

12 Longitudinal Wave direction of disturbance direction of wave transfer of energy

13  Learn how to measure amplitude, wavelength, and frequency.  Calculate a waves speed  Collect data to investigate how to change frequency in an experiment.

14  Height  Speed  Lengths  Also known as: Amplitude Wavelength Frequency

15  A crest is the highest point, or peak, of a wave.  A trough is the lowest point, or valley, of a wave

16  E:\Animations\wslm05_pg18_graph.html water level at rest fixed point crest trough

17  Amplitude for a transverse wave is the distance between a line through the middle of a wave and a crest or trough.  Amplitude is an important measurement because it indicates how much energy a wave is carrying.

18  The distance from one wave crest to the next crest is called the wavelength.  Can also be measured from trough to trough.

19  The number of waves passing a fixed point in a certain amount of time is called the frequency.  It measures how often a wave occurs.

20  When frequency increases more wave crests pass a fixed point each second. That means the wavelength shortens.  So, as frequency increases, wavelength decreases.  The opposite is also true.  Look at picture on page 498

21  The graph of a transverse wave looks like a wave itself  The graph of a longitudinal wave looks like a spring of coils.  Page 499

22  The speed of any wave can be determined when both the frequency and the wavelength are known, using this formula:  Speed= wavelength * frequency  S= λ f  Look at the example on page 501

23  Different types of waves can travel at very different speeds.  Light waves travel through air almost a million times faster than sound.  Example: Thunder and Lightening

24  In a stormy sea, 2 waves pass a fixed point every second, and the waves are 10 m apart. What is the speed of the waves?  S= λ f  S= 10 m/wave * 2 wave/s  = 20m/s

25 1. What two measurements of a wave do you need to calculate its speed? 2. What is the top of a wave called? Bottom? 3. What does the “Frequency” of a wave mean ?

26  Describe how waves change as they encounter a barrier.  Explain what happens when waves enter a new medium.  Identify ways in which waves interact with one another.

27  When waves interact with materials, they behave predictably.  Scientist call these behaviors: Reflection, Refraction, and Diffraction.

28  The bouncing back of a wave after it strikes a barrier is called reflection.  Water, sound & light waves all reflect.

29  Sometimes, a wave does not bounce back when it encounters a new medium.  Refraction is the bending of a wave as it enters a new medium at an angle other than 90 degrees.

30  You have seen how waves reflect off a barrier. For example, water waves bounce off the side of a pool. But what if the side of the pool had an opening in it?  Diffraction is the spreading out of waves through an opening or around the edge of an obstacle.  Occurs in all types of waves.

31  Sound waves diffract as they pass through an open doorway.  Turn on a TV and then walk into another room. You can still hear it because the waves spread out.

32  Interference is the meeting and combining of waves.  The adding of two waves is called constructive interference. It builds up, or constructs, a larger wave out of two smaller ones. Page 507  Destructive Interference is when one wave attaches briefly to the trough of another wave. The energy of one wave is subtracted from the energy of the other. Page 508

33  Explain what happens when waves encounter a medium that they cannot travel through?  Describe a situation in which waves would diffract.  Describe two ways that waves are affected by interference.

34


Download ppt " Explain how forces cause waves.  Explain how waves transfer energy.  Classify wave types.  Compare and contrast different wave types in an experiment."

Similar presentations


Ads by Google