Ocean Waves: Is it just an illusion of energy or is the water moving?

[Turkish]

Me and a friend were talking about wave surfing today and he said something like, water particles are not really moving with a wave. He said a water particle would stay at it's certain position and what we see is just the wave moving... i don't understand this, any truth in what he said? Or can someone explain the way ocean waves work?

Thanks.

 

[Shalmanese]

Think of the water as a skipping rope. You can send a wave down a skipping rope but all the bits of string only move either up or down. ENERY is moving, but not matter. Of course, this is only a pure description. In real life, the water will move slightly but not as fast as the wave.

 

[ShawnD1]

To see what Shal actually means, go find a very long rope or a long garden hose. Grab the rope or hose and try to whip it like a whip. You'll see the wave moving down the line and after the wave passes a certain part of the rope or hose, the part of the rope/hose goes back to where it was before.

You can also look at it like when people do the wave at ball game. The wave approaches a person, that person stands up and moves his hands, the wave goes by, that person sits down again. Look at it from a distance like the other side of the stadium. It looks like 1 big thing is moving but it's actually just a bunch of people (like water molecules) moving with the wave and going back to their original position after the wave has passed them.

 

[jmcoreymv]

Ocean waves are actually also a combination of tranverse and longitudinal waves, they end up having a circular motion to the particles.

 

[Mday]

Originally posted by: jmcoreymv
Ocean waves are actually also a combination of tranverse and longitudinal waves, they end up having a circular motion to the particles.

yup.

 

[silverpig]

At the science center here they have a wave tank with some cloudy particulate matter suspended in the water. There is a paddle which produces waves in the tank and you can see the individual particles move in circles as the waves travel through the water. If you have a glass tank at home you could probably try it for yourself.

 

[rjain]

The energy of any (physical) wave is contained in the continuous exchange of kinetic and potential energy. Look up simple harmonic oscillators for the introduction to how these systems work. Most waves can be modelled as a combination of SHOs arrayed in space.

 

[Fallen Kell]

Also the water does move because of the affect of the moon's gravitational force (hence why we have tidal forces of high and low tides).

 

[rjain]

I don't think he's talking about tidal fluctuations (which are also waves, but quite different from normal surface waves).

 

[sao123]

Would it be fair to say that the water moves the boundary of 1 wavelength...otherwise how would the wave wash up on shore then pull back??

 

[rjain]

sao: that is when the wave breaks, which is a very different situation than in the open water

 

[silverpig]

To be a little more accurate, there is a net movement of the particles. If you only take the first order terms of the motion, then you get ellipses for the individual particle motion, but higher order terms produce a stokes' drift, and you see the particles move forward ever so slightly with each wave. It's not much, but it does happen.

 

[Cashmoney995]

Get a rubber ducky, get in the bath tub and make a wave. You will see that the duck does not move with the wave a lot and generally stays in its place. Now take some food coloring put some in the middle of the tub and make another wave, the top of the water will move but the bottom does not move very much at all. Saw that experiment on Bill Nye the Science Guy! God what happened to classic programming!

 

[Turkish]

Wow I totally forgot about this thread I created! Useful stuff guys!!!
We always wondered about this, thanks for enlightning us