Simple Science: Making a Solar Still

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Have you ever heard of a solar still? It is a water purification device that you can make on your own by harvesting the power of the sun!

Making a diy solar still is a very simple science experiment to try with your kids. It will teach about the water cycle, particularly evaporation and condensation. It can also teach kids about solar energy.

We made ours with just a few common household items.

The great thing about this solar still project is that it would be useful to know how to do in nature if you had no fresh water to drink or in an emergency situation.

A solar still is an easy way to make distilled water, using the heat of the sun, or solar radiation, to create evaporation from salt water or any impure water and turning it into fresh drinking water, leaving the salt behind. It is also called solar distillation or solar desalination.

How to Make a Solar Still:

We made a very simpler version of a solar still with a glass bowl, a small glass jar and plastic wrap.

Fill a bowl with water and mix in a few tablespoons of salt until it dissolves in the water. Put a glass jar inside the bowl, right in the center, and push it down. You do not want to get any of the salt water into the jar, so make sure the water is not too full in the bowl.

Cover it all with clear plastic wrap and seal it tight. Put a rock in the center to weight it down and allow the pure water to fall into the jar. Place it outside in the warm sunlight for a few hours. What happens is the water evaporates and the moisture collects on the plastic wrap. The rock in the center traps it and gravity causes the water droplets to run down towards the jar and pool in the jar. Dirt, impurities and contaminants will be left behind in the larger bowl.

If you let it work for several hours, there will be a small amount of water in the jar. Taste it, and the water will not taste salty, but fresh. My kids thought this was SO cool! But they were a little afraid of tasting it.

A solar still can be made on a larger scale and with a higher yield in nature for survival situations if there is no potable water.  You can make a still by digging a pit and using a bowl or other container as a collector. You’d need a clear plastic sheet or a glass cover to place over the top. You can make clean water from any dirty water: seawater, contaminated water, or even urine if you are desperate.