A brief history of salt.
Salt is part of your food. You notice immediately if salt is missing, then the food tastes bland. You also notice when there is too much salt in your food.
We use salt for cooking. This is why it is also called table salt. Table salt consists of sodium and chloride.
Earth is deposited above the salt layer. The pressure of the earth compresses the salt and a salt diapir is formed. A salt diapir contains large quantities of salt.
Since everyone needs salt to live, people break down salt. In the past, people mined salt with a pickaxe. A pickaxe is like a hammer, but pointed on one side. It was very dangerous to get the salt. People worked underground in narrow passages. The tunnels often collapse and sometimes people die.
Salt is also important to preserve foods like fish and meat. Fish can go bad quickly and you can no longer eat it. If you put the fish in salt, it won't go bad because the salt takes the water out of the fish.