π Planet Earth π Rocks and minerals
Salt
π In short
Salt is a clear white mineral we put in food to make it taste good. For thousands of years people have also used it to keep food from going bad. Its scientific name is sodium chloride, because it's made of two elements: sodium and chlorine.
π€© Did you know?
- Seawater contains about 2.5% salt, plus other salts.
- Salt made by evaporation is 95 to 98% sodium chloride.
- In cold countries salt is used to melt snow on roads.
- Salt's name as a mineral is βhaliteβ.
π Find out more
π From the sea
Seawater is salty, so people put it in wide shallow pools by the shore, where the sun heats it, the water evaporates and the white salt is left behind to be collected.
π From underground
In some places there are thick layers of salt underground, formed from ancient seas that dried up. People dig mines into them and take it out in rocky blocks.
π‘ It was very precious
In the past salt was as precious as gold, and caravans carried it across the Sahara to trade for gold. It's said that the word βsalaryβ comes from salt!
π― In moderation
Your body needs a little salt to work well, but too much harms your heart and kidneys. So don't eat too many very salty foods like crisps.
πΈ More pictures
𧩠Test yourself
1 How do we get salt from seawater?
2 Why did people use salt in the past?
3 Seawater contains about ?? % salt, plus other salts.
4 Which picture shows βSaltβ?
π Discover more
π· Picture sources: Wikimedia Commons
- Luca Galuzzi (Lucag), edit by Trialsanderrors Β· CC BY-SA 2.5
- Dey.sandip Β· CC BY 3.0
