ATK Kids: Be a Salt Farmer | Life

Humans have been harvesting salt since prehistoric times. Get in on the action by creating a model ocean and harvesting your own coarse flaky salt at home!

SECURITY: Use the microwave

TIME: 10 minutes, plus 24-48 hours flash time

YIELD: Yields about 1 tablespoon of flaky salt

¼ cup distilled or filtered water

2 tablespoons kosher salt

Gather Equipment

Measuring spoon 1 teaspoon

8 inch square glass baking dish or pie dish

Tap water can contain tiny dissolved minerals that remain when the water evaporates (but are drinkable). They can give your salt a bitter flavor. You will add kosher salt to hot water in 1 teaspoon amounts – there are 6 teaspoons in 2 tablespoons. You can do this activity alone or with your friends and family.

Add water to the liquid measuring cup. Heat in the microwave until the water is steaming, 1 to 1 ½ minutes. Use oven mitts to remove the measuring cup from the microwave (ask an adult for help).

Add 1 teaspoon of salt to hot water. Stir with a spoon until the salt is completely dissolved and the water runs clear. Keep adding salt, 1 teaspoon at a time, and stirring until all the salt is dissolved in the water.

If there are any undissolved salt crystals after adding all the salt, strain the solution through the coffee filter before proceeding to step 3.

Place the baking dish in a place where it will not be disturbed. (A warm, sunny spot will help speed up evaporation.) Carefully pour salted water into a baking dish, this is your model of the ocean.

Let the baking dish sit for 24 to 48 hours or until all the water has evaporated. Use a magnifying glass to observe the model ocean a few times as it evaporates. What do you notice ?

Harvest your salt! Use a spoon to gently scrape the salt from the bottom of the baking dish (the salt will form large lumps). Salt can be stored indefinitely in an airtight container.

FOOD FOR THOUGHT

Or Are these salt crystals from?

The large square or rectangular salt crystals you harvested were from the tiny crystals or kosher salt you started with! When you dissolve salt in water and then allow the water to cool and slowly evaporate, the structure of the remaining salt crystals can change.

When mixed with water, the salt crystals dissolve into tiny ions. The hotter the water, the more salt you can dissolve in it. When dissolved salt ions meet, they lock together, much like puzzle pieces, and fall out of solution. As more salt joins them, the salt crystal gets bigger and bigger. The slower a salt solution cools, the more time the salt ions have to find each other and form larger crystals. Since you can let your salt solution cool slowly, you may have formed large salt crystals!

THE ORIGIN HISTORY OF SALT

All salt comes from the sea. Some comes from the oceans that cover most of the earth today. Other salts come from underground salt deposits left over from the drying up of ancient oceans millions of years ago. Here are two main ways to harvest salt:

To recover salt from underground deposits, manufactures water pumps for dissolving salt. Then machines pump the saltwater mixture into large tanks, which heat up. The heat evaporates the water, leaving behind the salt.

To harvest the slats from the ocean, the factories begin with large shallow pools of salty sea water. Over time, the water evaporates and the small salt crystals sink to the bottom. Manufacturers use special rakes to collect the salt. It’s similar to how you made your salt! (Some sea salts are made from heated seawater to speed evaporation.)

The salt you made is large flaky crystals. It looks more like sea salt than kosher salt or table salt. Use your magnifying glass to observe your salt crystals closely.