... very easy, very quick ...
So what's going on here in this picture? Well, let's see ... a couple of curious kids, some table salt, a water glass, a chunk of ice and a length of string ... a bit of a good science, I'd say! :)
Since yesterday dawned icy and cold (treacherous even!), I decided to do a neat little ice cube experiment with the boys. I could have looked through our upmteem science books for an activity, but instead I googled for it - and found this. It looked quick and easy (and fun) so we gave it a go!
We started with a cup of water, in which an ice cube was immersed. We tried to "lasso" the cube with a length of string, but of course that proved impossible:
Following the instructions of the video (see link above), we added salt to the water, but that did not seem to help us much - at first. The first time we performed this step, we shook the salt in the water, randomly and perhaps a bit aggressively. It didn't do much for the string, which still floated on the top of the water, ignoring the ice cube completely.
So we tried a different approach ...
We positioned the thread directly across the cube and poured the salt over it slowly and gently (so that it didn't knock the string off):
Oh yes, Earlybird was right in the mix, too - he wasn't going to miss this! :)
But did it work ...?
Success!
I was all prepared to discuss why this happened, when the boys suggested making it all happen in reverse. So the cube dangling in midair got another good salting ...
And then we waited and watched, wondering, ...
And, yes! Back into the glass of water went the ice cube - with a splash!
And we were right back where we started ...
So then we talked: What did the salt do to the water? To the ice? I asked the boys if they could recall a time in "real life" when we might add salt to ice, and why. (Aka treating icy steps and roadways.) So we thought it over and decided the salt does something to the water that makes it melt, but this was only half the answer - because what made the string stick to the cube?
Well, after a bit of research and brainstorming, we came to the conclusion that the salt sprinkled over the thread on the ice cube, allowed the ice to melt (lowering the freezing point from 32 to 15 degrees) and then, because the ice quickly refroze - it essentially trapped the thread (or stuck it) there.
Over supper, we brought this up to Daddy - chief snow removal technician in our house - for further clarification. I also suggested the boys ask their grandpa about it - he is a retired science teacher, and would definitely know the scoop on all this - he might even suggest a few more experiments for us!
So, that was a good bit of Fun Winter Science! Of course, this all immediately called to mind the infamous frozen tongue scene in the classic movie, A Christmas Story. (Remember poor Flick? Stuck? Stuck? Stu-huucck!!) We may have to watch that movie today as follow up. Very scientific, you know. ;)
Well, have a great Tuesday, everyone - thanks for sharing in our day! :)
