The sea is salty because the rivers that flow into it wash salts and other minerals out of the ground.
The salts dissolve in the rivers and the rivers flow into the sea.
As the sun evaporates the water from the sea to make clouds, it leaves the salts and minerals behind, so the sea is saltier than rivers and lakes.
Scientific theories behind the origins of sea salt started with Sir Edmond Halley in 1715, who proposed that salt and other minerals were carried into the sea by rivers after rainfall washed it out of the ground.
Here’s a killer poem we wrote.
John John is a brainy guy
Asking questions and wondering why
The salty sea which is such fun
When splashing in the waves and sun
Is not freshwater from the tap Or from a bottle with a cap;
So he will learn that salt and sea Mix just like sugar into tea
And that many other kinds of salt Dissolve into this briny malt, Sodium chloride, the salt of table Has other friends within its stable
Potassium Ch, magnesium Ch, and iodide
All flow solvent with the tide.
So now, dear John, you clever lad Off you go tell mum and dad.