Waves

[Ron]

I came across a book which states the following about (sea) waves:

 

Waves are the movements in the water body where water particles move up and down. It is important to note that water does not travel with the wave.

 

Can someone please explain me what does the second sentence (in bold) mean? If water doesn't travel with the wave, how does the water move forward? The attached image also shows waves moving the water forward. It's really confusing....

 

Thanks,

 

Ron

waves.bmp

[Mr Skeptic]

In waves over a flat surface, the water doesn't really move much, moves in circles or up and down while the wave itself travels forward. But the shore slopes upwards making it too shallow for the wave, which constrains the wave and makes it crest. I think there's a little forward motion overall, but it is certainly not like a flow of water. Plenty of the wave is under the surface of the water.

 

http://en.wikipedia.org/wiki/Water_waves

 

See the animations on that page.

[Newbies_Kid]

Is it correct if i said it is more like when you " waving" your blanket or a carpet. the blanket or the carpet won't get stretched which means no particle displacement in horizontal axis but only vertically.

[Ron]

In waves over a flat surface, the water doesn't really move much, moves in circles or up and down while the wave itself travels forward. But the shore slopes upwards making it too shallow for the wave, which constrains the wave and makes it crest. I think there's a little forward motion overall, but it is certainly not like a flow of water. Plenty of the wave is under the surface of the water.

 

http://en.wikipedia....iki/Water_waves

 

See the animations on that page.

 

You have said that the wave itself travels forward but the wave is made up of water. So why is it that the water does not travel with the wave?

 

Thanks,

 

Ron

[Mr Skeptic]

If you tie a rope to a tree and shake the other end, you can make waves in the rope. These waves travel forward, even though the rope does not (and cannot).

[Ron]

If you tie a rope to a tree and shake the other end, you can make waves in the rope. These waves travel forward, even though the rope does not (and cannot).

That is true but I would like to know the scientific reason why doesn't water (or the rope) travel forward with the wave. What exactly happens which gives the impression that water (or the rope) is moving forward where as they don't?

 

Thanks,

 

Ron

Edited September 25, 2010 by Ron

[Athena]

The illusration of the rope or the blanket is good, but sometimes the waves are higher than others, and a tsunami puts a lot of water on land. Surfers know, the waves aren't always the same, and there is greater or lesser movement of water, so it seems some moderation of the statement that the water doesn't move is necessary? Like what causes a normal wave isn't the same as what causes a tsunami wave, or if I knew more, would I know the cause of these different waves is really the same? Say the cause of the wave is energy, but the source of energy is different?