I was at the lake today and was noticing that the waves / wakes from boats and wave runners travel very far. I know that tsunamis can travel thousands of miles.

But I started to wonder why. Why can waves travel so far? Is it because water is not compressible?

Assuming still water, I assume that there are losses while the wave travel - some sort of opposing force like friction.

If the primary attributes are wave height, wave speed and wave width (front of the wave to the back of the wave), what attribute is most affected / reduced as the wave travels? Why doesn't a wave become still water quickly? Does it need some external force (current, wind, ??) to quiet a wave back down to still water?

Because energy can neither be created nor destroyed, only transformed.

The wave is the kinetic energy imparted by the boat to the water as the boat moves through the water.

Water molecules are uniform in size so the kinetic energy transfer is very efficient.

Because the energy transfer is very efficient and the water molecules are easily displaced, there's only a small amount of the kinetic energy transformed into heat.

The way to increase the energy transformation into heat would be to increase the friction by turbolence (other interfering waves and shallow bottom surface for the wave to scrape against on the the bottom.

If there were a bunch more boats such that the wakes were interfering / cancelling each other, then the waves would dissipate a lot quicker.

Tsunamis can travel very far because they have a lot of energy to dissipate as it would presumably take a lot of energy to make an earthquake occur.

the stupid water does not compress,
is there any chance that this question arose during a bout with the munchies ?

Even in water that appears still, there is a great deal of kinetic energy going on. An ice cube will melt faster in a washtub or a bathtub full of water than in a glass.

quote:

Originally posted by egregore:
Even in water that appears still, there is a great deal of kinetic energy going on. An ice cube will melt faster in a washtub or a bathtub full of water than in a glass.

I would think that a bathtub full of water has significantly more thermal mass than a glass of water.

quote:

Originally posted by Fenris:
I would think that a bathtub full of water has significantly more thermal mass than a glass of water.

That's the correct reason for the ice cube in a still bathtub. It's just thermodynamics and unrelated to waves. Mixing or agitation is a different issue.

quote:

Originally posted by bendable:
is there any chance that this question arose during a bout with the munchies ?

Wait, wait, wait... Is bendable, the king of off-the-wall questions, actually disparaging someone else's question as being merely pot-fueled navel-gazing?

Dang, son.

Literally, they don't go anywhere at all...

no disparagement intended, at all , consider it empathy ,
he is from cally , maybe he has a card

how many times in the last 1000 posts , have you
witnessed me disparaging ?

Just a little light-hearted ribbing, bendable. I wasn't actually accusing you of being mean/rude.

But it is surprising.

Cause waters all jiggly and what not.

So water might account for my jello belly then?

quote:

Originally posted by darthfuster:
So water might account for my jello belly then?

That gots to be jelly, jam don't shake like that.

I was wondering because there was a boat on the lake far enough away that you couldn't really hear it. Yet the waves that finally reaches shore were still strong enough to knock a couple of tots over.

So was just wondering how far waves could travel, why they didn't dissipate over distance.

Don't fret about the suggestion that a munchie causing substance induced wonder. I was out in the boat the other day and all I thought about was how many times per hour do women adjust their swimsuits.

I did study the situation enough to notice that most of the fabric pulls don't really reposition the suit, they are just verifications that it is where it's supposed to be. Maybe 1 in 5 or 10 fabric pulls actually is for a necessary readjustment.

Mark Twain said 90 percent of life is lived privately. I have similar thoughts about things. It is part of being human, having a cerebral cortex.

Amateur pharmaceutical experimentation aside, don't forget to include wind when trying to understand wave formation, propagation, and environmental hydrodynamics.

To the OP.
Some interesting reading here ;
http://www.seafriends.org.nz/oceano/waves.htm

I offer you no levity, there was once a wave that embraced me at Nags Head from the Canary Islands!