Solar-Powered Salt Removal

[ReneeMMM]

My 8 year old daughter is doing Solar-Powered Salt Removal for her Science Project. It's winter here and the average temperature will hover around freezing. We are trying to find a way to do the experiment outdoors but need suggestions to keep the water from freezing so that she can see the results of the experiment. We have considered using a plant heat mat under the cups of water (about 1/2 cup in each container) to help maintain an above freezing temperature of the water. We have also considered using heat lamps to try to replicate indoors.. Does anyone have better suggestions? Thank you for your ideas!

[theborg]

ReneeMMM,

Thank you for your question. I'm assuming you are doing the experiment on this site. I performed this experiment with my 8 year old as well. Whilst it wasn't as cold as you are describing, we didn't have much sun as we live in an area that rains a lot. Due to the lack of sun, it took a long time to see results.

This experiment works on the principles of evaporation and condensation. For the source water to evaporate it has to warm up enough to do so. This is where the sun comes in. If it is below freezing, even in direct sunlight, you may still have a hard time getting results. Even though you desire to put the experiment outdoors, if you had a windowsill that gets lots of sun, it would be much easier for you to see results whilst controlling the environment. Another idea is if you have heat lamps, you could try simulating the sun instead, by placing the brine solutions in such a way that they each receive the same amount of light/energy from the lamps and enough to promote evaporation from each.