A solar still is a useful way to distil and purify water. Solar stills don’t need much in the way of equipment or materials, and are very easy to make.
They don’t work very quickly, so are better suited to providing purified water each day rather than an instant water supply.
How Does A Solar Still Work?
A solar still uses the sun’s heat to evaporate moisture from damp earth or green vegetation in a hole in the ground. A plastic sheet covering the hole collects the moisture as condensation, which then drips into a container.
The evaporation and condensation means that only clean water is collected. Any dirt, impurities and bacteria are left behind.
Materials Required To Make A Solar Still
You don’t need much to make a solar still. The main materials required are a plastic sheet and a bucket or container to collect water. You’ll also need something to dig a hole with, as well as some rocks to hold down the plastic sheet. A tube for drinking is optional, and allows you to drink the collected water without disassembling the solar still.
How To Make A Solar Still
Dig a hole in the ground, with a diameter smaller than your plastic sheet. Add some green leaves or vegetation to the hole.
The vegetation contains moisture, which will evaporate in the solar still to be collected. You could even add some containers of water that you’ve collected from another source that needs purifying. Water will evaporate more quickly from wide, shallow containers. The solar still will still work without the added vegetation or water if the soil is moist in the hole. Additional sources of moisture will speed up the process.
Place a clean container for collecting water in the middle of the hole. If you are using a tube for drinking, place one end in the contained and the other outside the hole. Make sure, however, that dirty water can’t run down the tube into the container.
Cover the hole with the plastic sheet, supporting the sheet around the edge with smooth rocks that will not rip the sheet. Add another smooth rock in the middle of the plastic sheet over the container to weigh down the centre. Water will drip from the lowest point of the plastic sheet so ensure the container is directly below.
The solar still is now built, and just needs the sun to work.
How To Use A Solar Still
Once you have built your solar still, leave it to work while the sun is out. Moisture will gradually evaporate in the warmth under the plastic sheet, and will condense on the bottom of the sheet. It will run to the lowest point of the sheet and drip off. The container, which is below the lowest point of the sheet, will collect the water as it drips off.
After a few hours, check the container and you should have started collecting some clean, purified water for drinking.
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