Why radio waves cannot travel through water?

Answer 1

Radio waves do not travel well through water.Radio waves travel at the speed of light, and just like light, are absorbed by water, in the same way as the deeper you go the darker it gets. Ultra long radio waves travel the best in water, but even then only a few hundred metres.

Radio,visible light, infrared, ultraviolet, x-rays, microwaves and various other kinds of waves turn out to all be the exact thing. The only difference between them is the "wavelength" of the wave. In any wave something moves back and forth and the length of one complete cycle is called the wavelength. It turns out that all of these waves are able to move charges around - sort of. The thing is that the radio and waves with longer wavelengths move charges better than visible light and x-rays. That's because the shorter the wavelength, the faster the charges have to move to keep up. And moving all those charges around sucks up a lot of energy from the wave.

So, in fact, the saltier the water, the less able radio waves will be able to penetrate through it. By the way, using the same sort of reasoning you can explain why metals are not transparent :-P .

Answer 2

Radio waves cannot travel through water because water molecules absorb and scatter the energy of the waves. The absorption is high because water molecules are polar, making them interact with the electric field component of the radio waves. As a result, radio waves are attenuated quickly and cannot propagate effectively through water.