How do waves form and dissipate in water?

[primarygun]

Hello everyone,
Today I saw some waves in my physics lessons. A stone drops into water, and waves are created and spread from source to surroundings. Finally, the water became calm again.
What's the most proper explanation for that?

I think: Water molecules gain energy after being hitting, they collide the others.
By law of conservation of momentum, it is rather obvious to see the total amount of kinetic energy decreases after a collision. Finally, it becomes 0.
Is my explanation correct?

 

[HallsofIvy]

"By law of conservation of momentum, it is rather obvious to see the total amount of kinetic energy decreases after a collision."

That is certainly not true. "conservation of momentum" has nothing to do with kinetic energy decreasing. If fact, in the standard "perfectly elastic" collision problems both momentum and kinetic energy are conserved.

What causes water waves to "die down" is the fact that the collisions are NOT perfectly elastic. Friction degrades some energy to heat.

 

[wais]

Your explanation is partially correct. The creation of waves involves the transfer of energy from one point to another through a medium, in this case, water. When the stone drops into the water, it creates a disturbance in the water molecules, causing them to move and transfer energy to the surrounding molecules. This transfer of energy results in the formation of a wave. As the wave travels away from the source, the energy gradually dissipates, and the water returns to its calm state. So, while the collision does play a role in creating the initial disturbance, it is the transfer of energy through the medium that causes the wave to form and eventually dissipate. Additionally, the law of conservation of energy also applies here, as the energy from the stone's impact is transferred to the water molecules and then gradually dissipates. Overall, your understanding of the basic concept of waves is on the right track. Keep exploring and learning more about this fascinating topic!