What are some examples of when waves are useful and harmful?

[needingtoknow]

Homework Statement

What are some examples of when waves are useful and harmful?

The Attempt at a Solution

The examples for helpful I have so far are sound waves that allow us to communicate with one another and radio waves that enables us to use WiFi and cellphones. However I am not too sure about radio waves because they are electromagnetic waves and in the textbook it states that all vibrations require a medium to transfer waves, but electromagnetic waves do not require a medium so I am unsure about radiowaves. I also added that waves are an efficient form of transferring energy : sound, radiation, and thermal.

The examples for harmful I have so far are seismic waves that cause earthquakes and tsunamis and sound waves that can be a nuisance at times.

 

[HallsofIvy]

Homework Statement

What are some examples of when waves are useful and harmful?

The Attempt at a Solution

The examples for helpful I have so far are sound waves that allow us to communicate with one another and radio waves that enables us to use WiFi and cellphones. However I am not too sure about radio waves because they are electromagnetic waves and in the textbook it states that all vibrations require a medium to transfer waves, but electromagnetic waves do not require a medium so I am unsure about radiowaves.

So what? The question was about waves, not "vibrations".

I also added that waves are an efficient form of transferring energy : sound, radiation, and thermal.

The examples for harmful I have so far are seismic waves that cause earthquakes and tsunamis and sound waves that can be a nuisance at times.

 

[voko]

Think again about seismic waves and earthquakes: what is really the cause and the effect here?