system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is the ocean salty and rivers fresh water?
gpt
Rain has no salt in it.

The land has some salt in it.

When rain falls on the land, it runs downhill into the river and then into the ocean. As it goes, it picks up some salt from the land.

Water leaves the ocean when it evaporates and becomes clouds. Clouds don't have salt in them. And clouds are where the rain comes from.

If we drew a picture of how the water goes through all these places, we would see that the water picks up salt on the land, but does not bring salt with it from the ocean into the clouds.

Which means the salt is getting left behind in the ocean.

Slowly, over a long long time, salt is moving from the land to the ocean.