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## Middle school physics - NGSS

### Course: Middle school physics - NGSS>Unit 4

Lesson 2: Mechanical waves and light

# Mechanical waves and light

NGSS.MS:
MS‑PS4‑2
,
MS‑PS4.A.1
,
MS‑PS4.A.2
,
MS‑PS4.A
,
MS‑PS4.B.4
,
MS‑PS4.B
Mechanical waves and light waves are two different wave types that can both be represented with a model. Learn about a key difference between these two waves and which wave properties can be represented as the brightness and color of light. Created by Sal Khan.

## Want to join the conversation?

• What types of energy in thermal energy.
• Thermal Energy is the energy that heat (or the lack of) produces. If you use a thermal imaging camera, you'll see that a stove top burner perhaps, is far brighter then the inside of a refrigerator, as the burner is HOT and the fridge is COLD.
• at he says mechanical waves are the ones you "see" most often, however "seeing" is actually your eyes sensing the differences in light waves, so wouldn't light waves be tyhe ones you see more often?
• He's talking about "seeing the subject" of the kind of wavelength.
(1 vote)
• ok sal khan you may know now but for the kids who may not under stand. Sound waves enter the outer ear and travel through a narrow passageway called the ear canal, which leads to the eardrum. The eardrum vibrates from the incoming sound waves and sends these vibrations to three tiny bones in the middle ear. These bones are called the malleus, incus, and stapes. oh and i forgot to mention this was at
• What is the trough
• Why do waves have to be so tall and are some waves short?
(1 vote)
• Because that shows you the amplitude and of how much mechanical energy is affecting it. A example is if you press down on water compared to doing but much faster, as this results in doing it faster to have higher waves from you transferring more mechanical energy.
(1 vote)
• Why do waves need to have pointy on the top?
(1 vote)
• Not all waves are pointy on the top however all waves have some sort of slope. So the waves here are pointy on the top because they are sine waves and the pointyness is dependent on the waves amplitude. Hope this helps
(1 vote)
• Wait, so... Radio is light? and it turns into sound?
(1 vote)
• Visible light is a small part of the electromagnetic spectrum. Radio waves are light except that we can't see it or hear it. Our radio converts the radio wave into sound.
(1 vote)
• Did you know that they use peak in hospitals?
(1 vote)
• Why is it that the amplitude of an electromagnetic wave determines its brightness, and its frequency dertermines its color? Similarly with sound waves, why is it that its amplitude determines its volume and its frequency determines its pitch? I don't exactly understand how they correlate, as in frequency to colour.
(1 vote)
• Brightness refers to the intensity of the color and depends on the amplitude or the distance between the midpoint and the peak of the wave. The higher the amplitude of the waveform, the more intense and bright the color. Finally, saturation referred to color purity which is determined by uniformity of the wavelength.
(1 vote)
• Sal is just hurting my brain more that building it

Upvote if you agree
(1 vote)