In this video, we're going to talk about waves, specifically transverse waves and longitudinal waves. But let's focus on waves first. Waves can transfer energy and information from one place to another.
It's basically a disturbance. And here is an example of a wave. The top part of the wave is known as the crest.
The bottom part of the wave is known as the trough. The amplitude of the wave is the distance between the peak of the wave and its midpoint. This right here is the length of the wave, also known as the wavelength. You could also measure the wavelength by taking the distance between two peaks of the wave or two troughs of the wave.
So this... is also equal to the wavelength as well. Now the speed of the wave can be calculated by multiplying the wavelength by the frequency.
The frequency is basically the number of cycles that occur per second. If you take the number of cycles and divide it by the time you can get the frequency. The period is the time it takes to complete one cycle so taking the total time and dividing by The number of cycles that occurs will give you the period.
The frequency is 1 over the period, the reciprocals of each other. The frequency can be measured in hertz or 1 over seconds. The period is typically measured in seconds.
So those are some equations that you may need to know when dealing with waves. Now, let's talk about transverse waves. What do you think a transverse wave is? The wave that we drew earlier is an example of a transverse wave.
The reason why it's a transverse wave is because the wave is moving in the x direction but the oscillations are in the y direction. Anytime the oscillations are perpendicular to the direction of the wave motion we're dealing with a transverse wave. Example of transverse waves include water waves, let's say if you're on a beach and you see those waves on the ocean, those are transverse waves. EM waves are also transverse, so these are electromagnetic waves such as light waves, radio waves, infrared rays, x-rays, gamma rays, ultraviolet rays from the sun.
All of these are transverse waves. Another example is if you have a string and if you pluck the string, that's going to create a transverse wave. It's going to oscillate up and down while appearing to move left and right.
The next type of wave that you need to be familiar with are longitudinal waves. Now, longitudinal waves are different than transverse waves. In transverse waves, we said that the oscillations and the direction of the wave motion They're perpendicular to each other. Well, for longitudinal waves, the oscillations are parallel to the direction of the wave motion.
So let me see if I can draw a visual illustration. So notice here we have a region of compression. And here the wave is expanded, sometimes known as a rarefaction.
So the wave is moving in the positive x direction. But notice that the oscillations are not in the y direction. The oscillations are in the x direction.
Here, this wave is being compressed in the x direction. And here it's expanded. So when you have these regions of compression and expansion, you're dealing with a longitudinal wave. the oscillations are in the same direction as the direction of the wave itself.
A good example of a longitudinal wave is a sound wave. Sound waves are basically pressure waves. In a sound wave, you would have a region of high pressure where the molecules are very close to each other, and you'll have regions of low pressure where they're more spread out. So sound waves is a good example of longitudinal waves. And so that's basically it.
So remember, Logitudo waves have their oscillations parallel to the direction of the wave motion. but transverse waves have oscillations that are perpendicular to the direction of the wave motion.