Water comes in different shapes and sizes too. Three of the most important are oceans, lakes and rivers.
Key idea
An ocean is a huge body of salt water. A lake is a body of water with land all around it. A river is water flowing across the land in a long channel.
Why it works
Rivers carry rain and melted snow downhill. Some flow into lakes, and many end in the ocean. The oceans are salty, but most lakes and rivers are fresh water, the kind people and animals drink.
Worked example: A very big lake
Are all lakes small?
- Some lakes are tiny ponds.
- Lake Superior, one of the Great Lakes, is so big you cannot see across it.
Answer: No. Some lakes are huge.
Common mistake
Children may think a lake and an ocean are the same, or that all water is salty. Oceans are salty and connected to each other. A lake has land all around it, and most lakes are fresh. A few, like the Great Salt Lake, are salty.
For the grown-up. Find a lake and a river near you on a map. Which way does the river flow? Where does it end?