Hey friends 🌊👋

Have you ever gone swimming at the beach, accidentally tasted the water, and immediately made that face? 😖 Yeah… it's salty! But have you ever stopped and thought—why is the sea salty, but rivers and lakes aren't?

Let's talk about it! It's way more interesting (and kind of cool) than I expected when I looked into it. 💬

It didn't start salty

Believe it or not, when the Earth was young, the oceans weren't salty at all!

They started off more like big pools of rainwater. So where did all that salt come from?

Blame the rain 🌧️ + rocks 🪨

Rain is slightly acidic (because it absorbs a bit of carbon dioxide from the air).

When it falls on land, it slowly breaks down rocks. This process pulls tiny bits of minerals—especially sodium (salt!) and chloride—out of the rocks.

These minerals flow into rivers and streams, and eventually… they all end up in the ocean.

So, rivers may taste fresh, but they're constantly delivering small amounts of salt to the sea, every day, all over the world.

So why aren't rivers salty too?

Good question!

Rivers are always moving and being refreshed with rain and runoff, so any salt that gets in is quickly diluted or carried away.

But oceans? They don't really "spill out" anywhere. Salt goes in… and stays in. Over millions of years, it built up. That's why seawater is salty today.

How salty are we talking?

Pretty salty! If you took one liter of seawater and let it dry out, you'd be left with about 35 grams of salt — roughly six teaspoons 🧂😲

Some places, like the Dead Sea, are even saltier because they have no rivers flowing out and super strong evaporation.

But here's something cool…

The saltiness of the ocean isn't just random. It actually helps sea creatures survive, affects ocean currents, and even influences our climate. Yep, salt plays a big role in keeping the planet in balance!

Now I'm curious — did you already know why the sea is salty? Or is this your first time hearing the full story?

Drop me a comment if you learned something new today, and tag a curious friend to share the fun! 💬💙