yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Wave transmission | Waves | Middle school physics | Khan Academy


3m read
·Nov 10, 2024

When we're talking about waves, transmission is when a wave passes from a material into another one. For example, here we have the sun, 93 million miles away on average, and imagine the different materials that the light has to travel through from the sun to say hit one of these sand particles right over here.

Think about what it needs to be transmitted through. Well, it's going to travel through 93 million miles of the vacuum of space, and that's one of the amazing things about light waves is that they don't need a medium; they can travel through vacuum, through emptiness. But then, it's going to travel through several miles of Earth's atmosphere, so it's going to travel through several miles of Earth's atmosphere.

It'll hit these lenses of these sunglasses; it'll actually travel through the lenses of the sunglasses. The sunglass has some width or some depth to it, and then it'll go out onto the other side, and it will hit the sand right over here.

Now, one thing you might realize is the amount of transmission and what gets transmitted is dependent on the wavelengths of the wave, in this case, the wavelengths of light, and also about the material that they are going through.

So, for example, these sunglasses right over here, many sunglasses try to keep out UV light (ultraviolet light), which is a higher frequency than visible light. But that's what causes sunburns, and that can also damage your eyes, so those high frequencies are not making it through.

We could also see that this sunglass right over here kind of has an orangish color, which means that things that are closer to that end of the spectrum, closer to the red, the oranges, and the yellows, are getting through, which means that it's filtering out blue light.

So the blue light isn't getting transmitted through as much as, say, the red, orange, and yellow light, and that's why we see this as red, orange, or yellow. And then, of course, the light will get to that sand particle.

Now, transmission, as I mentioned, isn't just about light waves. We could talk about one of our other favorite types of waves; for example, sound waves. If you are in a room, you have probably experienced the fact that even if you were to close the door—and I do this a lot because I record a lot of videos—this is me in my little closet recording a video.

This is a top view of what I'm doing right now. A lot of times, my kids are in other parts of the house, and they're making a lot of noise. As we've talked about, sound waves are nothing but traveling pressure waves through the air. Those air particles are knocking one into another, but in order to make it to me, they need to get through that wall.

The way they do that is they get transmitted through that wall, so those air particles make the particles—or make the atoms or the molecules—in the wall start vibrating. They bump into each other, and then the particles on the other side of the wall will bump into the air in my little closet, and then we will have, once again, the sound waves make it to me.

Now, the overall magnitude of the sound, the volume of the sound, will likely be diminished, and not all of the frequencies of the sound will be transmitted equally. Different frequencies of sound waves are better at traveling through certain materials, just as we talked about with light waves.

So now, when you look at the world around you, or you hear the world around you, or look at other types of waves, just think about how it's transmitting from one material into another.

More Articles

View All
Endothermic and exothermic processes | Thermodynamics | AP Chemistry | Khan Academy
Before we get into the terms endo and exothermic, we need to look at some other thermodynamics terms that are used. For example, system: the system refers to the part of the universe that we are studying. For our example, we’re going to consider a monatom…
Sex Myths | Original Sin: Sex
After 100 years of sex education appearing in schools around the globe, young people are more confused than ever. Many blame this on political agendas, which they believe stand in the way of a student’s right to know. It’s profoundly shocking that you wou…
Your Top Questions on Economics & Investments Answered: Part 2
I was asked about money and saving and investing, and what the most important things are. Start with the basics: what do you need, for how long, and what do you have in relationship to that? That’s most fundamental. Then, you can get into the more esoter…
Never Let A Man Control Your Financial Destiny
50% of marriages within 7 years fail, not because of infidelity, but because of financial stress. The other issue that’s so important after you turn 18 as a woman is that you have to maintain a financial identity in our system. Yes, if you don’t have a cr…
A Brief History of Grand Canyon National Park | National Geographic
The Grand Canyon. Enormous, iconic, breathtaking. 2019 marks Grand Canyon National Park’s 100th anniversary. But how did it get to be such a beloved destination? Archeological artifacts suggest that people lived in and around the canyon some 12,000 years …
15 Questions to Unlock Your Potential
Hey, we’re going to have a heart-to-heart today, all right? This is a secret tool that we’ve used for decades. Every couple of years, we go through these exact questions to have a reality check with ourselves, and today we’re going to do it together. Save…