It's surprisingly noisy. Volcanoes hiss, rain patters down and sea creatures snap, squeak and croak as they search for food or flee from their enemies. During World War 2, submarine crews were startled by strange crackling sounds, which turned out to be snapping shrimps. (Snap your fingers - this is the noise these shrimps make.)

The noisiest creatures are the mammals. Whales send out different calls when they court one another, sense danger or want to keep the pod (group) together. Whale sounds can travel hundreds of kilometres (miles) underwater. Look for a record of whale 'songs' in the library. Porpoises, too, have a highly developed communication system and make clicking noises to 'talk' to one another.

Hydrologists, scientists who study water, have compared the amount of water in oceans with the amount of water on land. The result of their findings is referred to as the water budget. Hydrologists add and subtract the amount of water in much the same way as families add and subtract money in household budgets. After calculating how much precipitation falls on the oceans and how much water evaporates from the oceans, then subtracting evaporation (loss) from precipitation (gain), hydrologists have found that the oceans lose about .36 x 10" cubic meters of water per year. More water evaporates from oceans than precipitates into oceans.
Then hydrologists made the same calculations for land and found that a surplus of about .36 x 1014 cubic meters of water falls onto the land per year. The excess amount of water that precipitates onto land is equal to the excess amount of water that evaporates from oceans!
The reason that the land doesn't become soggy and the oceans don't dry up is that the extra precipitation on land ends up in rivers and groundwater. This excess water flows, drips, and seeps its way back to the oceans, where evaporation occurs on a large scale, continuing the hydrologic cycle.

.