How to Purify Water for an Elementary Science Project
You can teach elementary school students about how to purify water with a solar water purification system, or a solar still, using a few household supplies. Solar stills use evaporation to rid impurities from water. As the water heats up it turns into a gas and rises upward toward the stretch wrap, then travels to the center and falls into the cup. The collection of water through evaporation in a solar still purifies water for consumption.
Things You'll Need
- Pitcher
- Water
- Salt
- Wooden spoon
- Large bowl
- Short cup
- Stretch wrap
- Tape
- Small weight
- Sunny location
Instructions
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1
Fill a pitcher with water and add a lot of salt; stir the water with a long wooden spoon until the salt dissolves.
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2
Pour two to three inches of the saltwater solution into a large bowl. Set aside the pitcher.
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3
Place a short cup in the center of the bowl. The rim of the cup should stand higher than the water level, but lower than the rim of the bowl.
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4
Seal the bowl with the stretch wrap.
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5
Place a small weight, such as a rock, in the center of the stretch wrap, which should be directly over the empty cup.
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6
Set the bowl on a flat surface in a sunny location and leave it there for several hours.
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7
The water collected inside the cup has been distilled and will taste non-salty. Taste the water or use a saltwater tester to prove that the water is no longer salty.
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8
Consider retesting the project by adding other things to the water, such as sugar or food coloring, to see what the solar still will purify.
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1
Tips & Warnings
If the stretch wrap does not stay secured to the bowl, tape the stretch wrap to the bowl.
The longer you leave the solar still in the sun, the more water will be collected in the cup.
Avoid using a sharp weight, which may puncture the stretch wrap.
References
Resources
- Photo Credit water drop is falling down and impact with water surface image by Alexander Potapov from Fotolia.com
