Sunday, July 24, 2011

More Air Bubbles in the Ice

After investigating the cause of the white spots in our ice cubes, for Science Sunday last week, and determining they were mainly made from air bubbles, corralled into a group, as the water froze around them, we had a couple of commenters suggest boiling the water twice, might remove more of the bubbles.

Naturally, we had to give it a try. We set up four cups, one with unboiled tap water, as a base line, one with filtered water boiled once and covered, to keep additional air from getting into it (or it at least that was the hope), one with the water double boiled, and one double boiled and covered.

We had an indication, almost immediately, that double boiling was not going to remove the white spots from our ice. We could see air bubbles, along the bottom and edges of the inside of the cups, as soon as we poured the boiling water into them, whether it was boiled once, or twice.

And, sure enough, when we checked the ice cubes later, all four had about equal sized areas of white.

The ice cubes from the covered cups were interesting though, because they had crystal designs in the ice, where the bubbles seemed to spray out from the white spots toward the edges. Was this because the covered water froze faster, or maybe because of the way the water drops condensed on the plastic wrap, and then dropped back down into the cup?

We really aren't sure, but now we have even more to look into. And, if nothing else, the designs in the ice were very pretty to look at in the sunshine.

It's great to be a homeschooler.

This post is linked with this week's Science Sunday link-up at Adventure's in Mommydom, where you can find more science projects and ideas for children.


Christy said...

All of your icy fun is pretty cool! Neat experiment.

Phyllis said...

Have you ever noticed that the ice you buy in bags usually doesn't have any white in them at all. Wonder why that is? They do fast freeze it. Could it be how long it takes to freeze determines how much air is in it and therefore how much white spots? Interesting investigations!

Raising a Happy Child said...

I did some additional reading about clear ice since I got curious, and they do say that they use special equipment in the restaurants to produce clear ice (similar to natural icicle making when water freezes in layers).

Ticia said...

Very interesting. You do so good at following up on these things.