Raisins

We started experimenting with raisins way back in October.

First, we made predictions about what would happen when we put them into bubbly water. Then, we tested to see if our predictions were accurate or not. We found that the bubbles stuck to the raisins, and that some of the raisins would dance up to the top of the water, then fall back down. Here's what the testing looked like:

Our next experiment was a control test. We put the same number of raisins (from the same raisin brand) to the same plastic cups with the same quantity of water in them. Everything was the same as the first test, except that we used plain tap water instead of bubbly water. With plain water, the raisins just stayed on the bottom. Many raisins did have a couple of bubbles on them, but not nearly as many.

Then, many of the scientists in our lab wondered what would happen if we did other things with the raisins. Someone wondered what would happen if we squished one after it sat in the water overnight. Dr. MacLellan hit it with a hammer and bits of it went everywhere! That didn't happen with an ordinary raisin.

Other colleagues wondered what would happen if we put the raisins in other kinds of liquids. So, we put them in vinegar, cooking oil, soda, extremely salty water, and hydrogen peroxide. Then, we left them on the windowsill to look at again in two weeks.

Pretty quickly, the raisins in plain water grew mold, so we threw them out. I didn't put a picture of that here, because it's pretty disgusting. The other liquids were mold-free, so there must be something about each of them that kept the mold from growing. Besides mold, in most of the other liquids, the raisins had swelled up and were floating on top of the liquid. Only the raisins in the oil were still dark, shriveled, and resting on the bottom of the cup.

Vinegar:

Soda:

Extremely salty water:
These ones had a layer of salt crystals growing across the top of the water, as well as square salt crystals on the raisins themselves.

Hydrogen peroxide:
These were lighter in color than the others.

Cooking oil:
These raisins didn't change at all, and none of the liquid had evaporated.

Bubbly water:

After about six weeks of sitting on the windowsill, most of the liquids had evaporated.The salty water was very interesting:

The cooking oil was still the same:

And the hydrogen peroxide was all gone, but the raisins were bleached white!

With the soda and the bubbly water, they eventually grew mold, but it took a while. None of the others had any mold on them.

This was a fun experiment!