Transcript waves
Waves, Sound, and Light Chapter 1
Bell Work 1. Name two ways you can apply force to a soccer ball.
2. Name two ways the force you apply can change the motion of the soccer ball.
W, S, L - 1.1 Vocab
Wave
– a disturbance that transfers energy from one place to another
Medium –
any substance that a wave moves through
Mechanical wave –
waves that transfer energy through matter
1.1 Vocab Cont.
Transverse wave
– a wave that travels in a perpendicular direction to its disturbance
Longitudinal wave
– a wave travels in the same direction as its disturbance
Bell Work 1. What is a mechanical wave?
2. What is a transverse wave?
3. What is a longitudinal wave?
Bell Work Fill in the chart like a Venn Diagram Longitudinal Wave Both Transverse Wave
1.2 Vocab
Crest
– the highest point, or peak, of a wave
Trough
– the lowest point, or valley, of a wave
1.2 Vocab Continued
Amplitude
– the distance a medium moves above or below its trough or crest
Wavelength
– the distance from one crest or trough to the next
Frequency
– the number of waves passing a fixed point in a certain amount of time
Bell Work 1. Describe how forces start waves.
2. Does water moving through a hose qualify as a wave? Explain why or why not.
Bell work
Make a simple diagram of a wave – label crest, trough, amplitude, and wavelength.
Bell Work Get out a pencil and put everything else away. Then, grab a sheet from Justis and answer the true/false questions on the front.
Bell Work How could you measure each of these things? What problems might you encounter in doing so?
1. Width of a door opening 2. Volume of liquid 3. Length of time
Bell Work 1. What is a medium?
2. Give 3 examples of mediums.
Wave Lab Purpose: How can a transverse wave and a longitudinal wave be demonstrated?
Bell Work 1. Explain how to make a wave with a rope.
2. Explain how to make a wave with a slinky.
Bell Work 1. When you look in a mirror what are you seeing?
2. What are some examples of waves?
Notes 1.3
Reflection
– the bouncing back of a wave after it strikes a barrier
Reflection Any type of wave can be reflected.
We will look at the reflection of Sound , Water and Light Waves.
Reflection best occurs from flat, hard surfaces.
After reflection, a wave has the same speed , frequency and wavelength , it is only the direction of the wave that has changed.
Refraction
– the bending of a wave as it enters a new medium at an angle other than 90 degrees
Refraction • Any type of wave can be refracted, which means a change of direction.
We will look at the refraction of Water Waves , Light Waves and Waves from Earthquakes .
• Refraction can occur when the speed of a wave changes, as it moves from one environment to another.
After refraction, the wave has the same frequency but a different speed , wavelength and direction.
• When a wave enters a new environment, its change in speed will also change its wavelength (see the definition of wavelength ).
Diffraction
– the spreading out of waves through an opening or around the edge of an obstacle
Diffraction • Any type of wave can be diffracted.
A diffracted wave will "spread out".
Diffraction occurs when the wavelength of a wave is of a similar size to an obstacle or a gap in a barrier.
• After diffraction, a wave will have the same speed , frequency and wavelength .
Interference
the meeting – and combining of waves
Bell Work 1. What is reflection?
2. Give an example of reflection.
3. What is refraction?
4. Give an example of refraction.
Bell Work 1. What is diffraction?
2. Give an example of diffraction.
3. What is interference?
4. Give an example of interference.
Bell Work 1. What is an echo an example of?
2. What do all waves travel through?
3. What is the amplitude measuring?
Bell Work Choose a type of wave that we made during the wave lab in class. Draw a small picture of the wave that was made and describe what type of wave it was and how the wave was made. Show in the picture the
direction of disturbance
and
direction of the wave.
Be sure to include how you know whether it is a
transverse
or a
longitudinal
wave.