How a river is formed
The water in a river flows from it’s source. This could be melting ice, rain and a mountain. Rives have main channels, in between them there are the banks and if too much rain or water gets into them, they might burst and start to flood. At the bottom of the main channel there is the bed, made out of dirt. The water can meander. This means that the river bends. Also, the river ends at the sea. This is called the mouth.
Oceans and seas
Did you know, that the ocean covers 70% of the worlds surface? On the other hand, the Pacific ocean covers 30% of the world. Surprisingly, the world has lots of different oceans but one of them is the Indian ocean. Also, seawater is salty. Therefore, drinking it can get you really ill! An interesting fact, is that the ocean is bigger than the sea because the ocean is deeper.
A river starts at a mountain and ends at the mouth. Amazingly, river water is fresh even though, before drinking it you need to filter the water because it still has germs in it! Did you know, that when a meteor his the ground and it starts raining, it can form a lake? The lake will need continuous source of water or it might evaporate.