martinzoo

GB loves animals and the military…. weird combo, huh? This week he has been totally enraptured by a documentary on the Discovery Channel, called Ocean of Fear: Worst Shark Attack Ever. It features the story of the USS Indianapolis in World War II, and describes the sinking and the horrifying shark attacks that cost hundreds of soldiers’ lives.

One of the things that they stressed in the documentary was the fact that all these soldiers were trying to survive for days and days on the ocean with no fresh water, but that there was water all around them, and that it was terribly tempting to drink that salt water. This led to hallucinations in the soldiers and ultimately death. We discussed how there are times when you cannot drink water even if it’s right in front of you, even if it looks ok.

I’ve been reading lots of Science sites lately. And because of GB’s interest in the purification of water for survival, I went and looked around for this experiment. I’m hoping he never comes into a circumstance where he will need to use it, but it’s good to know anyway. I got this experiment from Home Science Tools.

You will need: A large bowl, a small beaker or glass, water, salt, food coloring, plastic wrap, and a rock or coin.

Salt the water to represent the ocean or polluted water.

I let GB taste the water to make sure it was good and disgusting…LOL!

Add food coloring so you can tell that it’s different from the purified water. We used a pretty Caribbean blue.

Place your glass container inside the large bowl and pour the salt water mixture into the bowl. Use enough to see it well, but not so much that your glass container floats.

Like this…

Now cover it with the plastic wrap. Make an airtight seal (use tape around the edges if you need to) and then put your rock or coin over the beaker. Since water will pool to the lowest point, when the condensation collects on the plastic wrap, it will drip right into your glass container. Put your bowl outside on a nice sunny day and wait.

We will check our results tomorrow.

After we finished setting up this experiment, we discussed other items the soldiers could have used out in the ocean to set this up. It would have been hard, but lots of things were floating around, so maybe they could have done it. We also pondered if GB was alone on a deserted island, how could he implement this process. He decided that he would use a hollow tree for the big container, a small hollowed out coconut for the small container, and he was hoping that he had a tarp or something else to use to control the condensation. It was a VERY interesting discussion.