Crave the Wave B

[bernard]

[adatta0517]

Hello. So I’ve been studying waves, and I don’t understand the difference between the medium and the actual wave. I get that the medium is what the wave moves through, but then what’s the actual wave? I’ll use the slinky coil as an example. When u vibrate your hands on one end, a wave passes through the slinky right? The slinky coil is the medium, but then what’s the actual wave?

Thank you!

[PhysicsFan]

Anyone have any practice tests for this event in its current form

[gz839918]

Anyone have any practice tests for this event in its current form

Hi there, and welcome to Scioly.org! We have a few old Crave the Wave tests on the Test Exchange Archive, which may help you. However, because Crave the Wave wasn't an event last season, and is new for this season, these past tests won't be exactly tailored to this season's rules, but you'll find that they're pretty similar. It may take a bit of time before the first publics Crave the Wave tests are released.

Happy studying!

[UTF-8 U+6211 U+662F]

Hello. So I’ve been studying waves, and I don’t understand the difference between the medium and the actual wave. I get that the medium is what the wave moves through, but then what’s the actual wave? I’ll use the slinky coil as an example. When u vibrate your hands on one end, a wave passes through the slinky right? The slinky coil is the medium, but then what’s the actual wave?

Thank you!

Hello! I would say that in your example, the medium is the slinky coil, and the wave is the up and down motion of the slinky coil. To give another example, in an earthquake, the medium is the ground, and the wave is the shaking of the ground. An interesting point about this is that while the wave itself moves, the actual medium stays in place. For example, when you talk, the sound waves can travel very far, but the individual air molecules move very little. Same with a slinky: if you get a long slinky and shake one end, the wave will travel "down the slinky" towards the other end of the slinky even though the slinky itself is not moving in that direction. Another thing is that some waves do not need physical media at all! For example light waves (which are waves in something called the electric and magnetic fields) can travel through a vacuum, which explains how Sun rays get to the Earth even though there is empty space between the Earth and Sun. Hope this helps!

[adatta0517]

Hello! I would say that in your example, the medium is the slinky coil, and the wave is the up and down motion of the slinky coil. To give another example, in an earthquake, the medium is the ground, and the wave is the shaking of the ground. An interesting point about this is that while the wave itself moves, the actual medium stays in place. For example, when you talk, the sound waves can travel very far, but the individual air molecules move very little. Same with a slinky: if you get a long slinky and shake one end, the wave will travel "down the slinky" towards the other end of the slinky even though the slinky itself is not moving in that direction. Another thing is that some waves do not need physical media at all! For example light waves (which are waves in something called the electric and magnetic fields) can travel through a vacuum, which explains how Sun rays get to the Earth even though there is empty space between the Earth and Sun. Hope this helps!
[/quote]

Ok, thank you!
Can you explain more about the electric and magnetic fields that it goes through? What exactly is that? And what is a vacuum?
Also, in your example of the earthquake, is the wave what we would typically imagine a wave to look like, with the simple up and down motion? Or is it something else? And like how is that motion created?
Another question I have is, say in the example of sound waves moving, why is it that just because one particle moves, the other particles have to move? Since it's not like the air particles are connected to each other or something? And how is the air vibrating?

And one more question
So in the slinky example when the final wave passes through, how come there's this tiny wave moving back towards the other end? Like how does it bounce back?

[knightmoves]

Another question I have is, say in the example of sound waves moving, why is it that just because one particle moves, the other particles have to move? Since it's not like the air particles are connected to each other or something? And how is the air vibrating?

The air molecules aren't "connected" to each other in the sense of being joined by little rods, but they do interact with each other. The molecules in air (or any gas) bounce off each other all the time.

There are a couple of different ways you can think about compression waves in air - you can either think of the air as a bulk medium, or as lots of individual molecules.

In the first case, you're going to think about air being elastic, and if you compress a bit of it, it wants to spring back. Think about putting your finger over then end of a plastic syringe and forcing the plunger in: it wants to spring back out because you've increased the pressure in the air in the syringe. (Don't do this with a fancy glass gas syringe in your school science lab, or the plunger will spring out and shatter on the floor, and you'll get a bill!)

Alternatively, think about all the molecules individually, bouncing off each other. If you make an area of increased density, there are more molecules bouncing off each other in that space, and so statistically, they are likely to move away from the place where lots of molecules are and towards fairly empty places.

Proving that these two pictures are equivalent is left as an exercise for the reader

[PlutoLikeScience]

Hello I have a quick question regarding one of the practice questions on the Scioly Wiki. I was wondering how it is possible to solve the following:

"If the frequency of a light wave is 2 Hz (2 cycles per second), what is the wavelength?"

Im just wondering how its possible to find the wavelength without the velocity. This is probably a dumb question but if someone could help me out it would be greatly appreciated.

[adatta0517]

Alternatively, think about all the molecules individually, bouncing off each other. If you make an area of increased density, there are more molecules bouncing off each other in that space, and so statistically, they are likely to move away from the place where lots of molecules are and towards fairly empty places.

Can you explain this part more?

That, and I have another question. In water when you move your hand up and down splashing it, doesn’t it create a transverse wave?

Another question lol:
So I've been reading from a site and here's a quote:

This characteristic of a wave as an energy transport phenomenon distinguishes waves from other types of phenomenon. Consider a common phenomenon observed at a softball game - the collision of a bat with a ball. A batter is able to transport energy from her to the softball by means of a bat. The batter applies a force to the bat, thus imparting energy to the bat in the form of kinetic energy. The bat then carries this energy to the softball and transports the energy to the softball upon collision. In this example, a bat is used to transport energy from the player to the softball. However, unlike wave phenomena, this phenomenon involves the transport of matter. The bat must move from its starting location to the contact location in order to transport energy. In a wave phenomenon, energy can move from one location to another, yet the particles of matter in the medium return to their fixed position. A wave transports its energy without transporting matter.

Here, the bat can simply just return back to its equilibrium position right? So that way, this one does require matter displacement but that matter just vibrates. (returns back to its original position after transferring energy to the ball) right?

[aakoala]

Hello I have a quick question regarding one of the practice questions on the Scioly Wiki. I was wondering how it is possible to solve the following:

"If the frequency of a light wave is 2 Hz (2 cycles per second), what is the wavelength?"

Im just wondering how its possible to find the wavelength without the velocity. This is probably a dumb question but if someone could help me out it would be greatly appreciated.

electromagnetic waves always have a constant speed; 3.00*10^8 meters per second. hope this helps!