Mystery #1Tier 1oceans and salt
Why is the sea so salty when the rivers and rain that fill it are not?
Every river that pours into the sea is fresh enough to drink. Rain falls fresh too. Yet the sea is so salty you could never gulp it down. Why is the sea so salty when the rivers and rain that fill it are not?
Your guess
Where do you think all that saltiness comes from, and why does it stay?
There's no single magic word to type, have a go in your own words, then reveal the answer to see how close you got.
Make a guess to unlock the hints and the answer.