What is the force that is actually pulling the wave down/pushing it up? I can find information talks about the medium used to create the wave can determine its frequency but not what is actually causing that pattern in particular as opposed to a straight line or even a loop d loop.
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The wave doesn’t move exactly “up” and “down”, it’s a visual representation of higher and lower pressure (in case of sound) and other measurable things such as electromagnetic field intensity in case of light.
Sound is produced by vibrating surfaces. They move back and forth and, consequently, push the air around them back and forth. This creates slightly lower/higher air pressure which then spreads around: if the pressure got higher than ambient in some point, then in one second a point (speed of sound * one second) away would experience the spreading pressure. So, the presure starts oscillating there as well.
For non-sound waves, like light, it works in a similar way: stuff starts changing back and forth at the origin point and then this movement spreads.
It depends on what kind of wave you are talking about. In a sound wave, essentially you have a lot of particles moving front and back very quickly, that have been “jumpstarted” by some kind of energy imput (for example, the vibrating strings you use to speak), forming a pressure wave.
There are a couple of good answers already but I get the sense you’re asking at a more general level — what is it that causes something to move like a wave?
The fundamental property of a waveform is that its second derivative is negatively proportional to its value. This is represented by an equation like x” = -kx where k is some constant of proportionality.
What this means tangibly is that when the value goes up, its rate of change goes down and pulls it back; and vice/versa. The “value” we’re talking about depends on the context of course. A few examples:
– Sound waves are waves of air pressure. A local area with higher pressure than its surroundings (more air molecules) will tend to dissipate because the particles repel each other. And again, vice/versa for low pressure.
– Light propagates as a wave because of the homogeneous Maxwell equations, which are two of the fundamental equations of physics. They explicitly imply that the second derivative of the electromagnetic fields are negatively proportional to the strength of the fields themselves.
– A wave that propagates down a rope. Here the “value” is literally the displacement of the rope at any specific point. When it’s large, the rope is pulled tight and tension pulls it back.
All of these follow the same basic principle, and more precisely the same mathematics (they’re described by the wave equation), and that’s why we say they behave like waves.
The wave doesn’t move exactly “up” and “down”, it’s a visual representation of higher and lower pressure (in case of sound) and other measurable things such as electromagnetic field intensity in case of light.
Sound is produced by vibrating surfaces. They move back and forth and, consequently, push the air around them back and forth. This creates slightly lower/higher air pressure which then spreads around: if the pressure got higher than ambient in some point, then in one second a point (speed of sound * one second) away would experience the spreading pressure. So, the presure starts oscillating there as well.
For non-sound waves, like light, it works in a similar way: stuff starts changing back and forth at the origin point and then this movement spreads.
It depends on what kind of wave you are talking about. In a sound wave, essentially you have a lot of particles moving front and back very quickly, that have been “jumpstarted” by some kind of energy imput (for example, the vibrating strings you use to speak), forming a pressure wave.
There are a couple of good answers already but I get the sense you’re asking at a more general level — what is it that causes something to move like a wave?
The fundamental property of a waveform is that its second derivative is negatively proportional to its value. This is represented by an equation like x” = -kx where k is some constant of proportionality.
What this means tangibly is that when the value goes up, its rate of change goes down and pulls it back; and vice/versa. The “value” we’re talking about depends on the context of course. A few examples:
– Sound waves are waves of air pressure. A local area with higher pressure than its surroundings (more air molecules) will tend to dissipate because the particles repel each other. And again, vice/versa for low pressure.
– Light propagates as a wave because of the homogeneous Maxwell equations, which are two of the fundamental equations of physics. They explicitly imply that the second derivative of the electromagnetic fields are negatively proportional to the strength of the fields themselves.
– A wave that propagates down a rope. Here the “value” is literally the displacement of the rope at any specific point. When it’s large, the rope is pulled tight and tension pulls it back.
All of these follow the same basic principle, and more precisely the same mathematics (they’re described by the wave equation), and that’s why we say they behave like waves.
don’t know how to mark this as answered but I think you folks nailed it. Thank you!
don’t know how to mark this as answered but I think you folks nailed it. Thank you!
The up/down thing is just a visual. Really what’s happening is the constituent particles of whatever medium supports the wave are getting squished together/spread apart. So if someone shakes a rope the waves look like a line, but only because the rope is itself linear. if instead you imagine a rock dunking into a pond, the ripples that spread out around it are in 2 dimensions on the pond surface, but a hemisphere underwater (you just can’t see that). if a speaker is emitting sound or a light is shining, the waves radiate out from it in every direction until something stops them. And the waves just consist of looser/denser packing of the stuff (air, water, electrons, whatever is there). Like a stop-n-go traffic jam.
The up/down thing is just a visual. Really what’s happening is the constituent particles of whatever medium supports the wave are getting squished together/spread apart. So if someone shakes a rope the waves look like a line, but only because the rope is itself linear. if instead you imagine a rock dunking into a pond, the ripples that spread out around it are in 2 dimensions on the pond surface, but a hemisphere underwater (you just can’t see that). if a speaker is emitting sound or a light is shining, the waves radiate out from it in every direction until something stops them. And the waves just consist of looser/denser packing of the stuff (air, water, electrons, whatever is there). Like a stop-n-go traffic jam.
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