Necessity is Truly the Mother of Invention

Author: Michele / Labels: , , , , , ,

Again, the pic is not of our experiement, but I wanted to share it with the friends and family who browse this blog.

Yesterday marked the first "official" day of our summer schooling program, although we had been doing work before then. We did the funnest experiment. Part of what we are doing prior to actually starting our first lesson on the coral reef, is learning about the ocean itself. We have learned the names of the oceans and where they are on a map (although memorization will be an ongoing proces. We are also learning what makes the ocean different from other bodies of water, both in terms of the salinity of the water and in the formations beneath. Tomorrow we will be looking at a diagram of a cut-away of the ocean floor (which I will be drawing today) and then making our own models, so I will get pics up of that. Yesterday however, we talked about the heaviness of the salt in the water, and how it makes the water sink compared to tap water.

I had found an experiment online and as the directions weren't very good, couldn't get it to work. Bless my husband, who sat there until he found an experiment online that did work, then tested it to make sure we could recreate it, then helped corral kids while we actually did it.

Luckily, I had an old water testing kit my mother had given me for aquariums that had small glass tubes. They worked perfectly. Here are a fairly concise set of directions. I hope you have as much fun with this as we did!

Take three small containers of water (100ml). Add food coloring of contrasting shades to each container. We made two of ours too close in color and it was harder to see the end result. Then add 1/2t salt to one of them and 1t of salt to the other. The third leave unsalted. With a dropper, squeeze half a dropper of water out along the edge of the tube, so it runs down the inside of the tube into the bottom. This will prevent the force of the water from mixing the colors.

First add the saltiest water. Next add the next saltiest water. Finally, put the plain water on top. What you should end up with are striped bands of colored water. Just to show what happens if you change things up a bit, make another tube, this time with the plain water on bottom, followed by the less salty and then the saltiest water. Discuss what happens and why. Why does the first tube stay banded and the second tube mix?

My kids thought this was akin to a magic trick and we did it probably 6-8 times. Then they had a great time shaking the tubes when we were done to mix the colors. This is a great chance to review color mixing too. :) Hope you have as much fun as we did.


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