But I did mention in my Chanukah activities round-up last night that our science has been somewhat less than rigourous lately. We are enjoying our readings and workbook pages in Mr. Q Earth Science, and I’m actually happier than I thought I’d be to be spending a year away from Life Science, but we aren’t doing a ton of experiments, probably because (sigh) I’m not (in real life) a deeply experimenty person. I don’t mind experiments, but don’t like Gathering Stuff. Plus, it’s cold outside and this week’s Mr. Q. experiments involve tracking the position of the sun, which is kind of a tough thing to do if it doesn’t put in an appearance from one week to the next.
But what we do have is lots and lots of olive oil…! So we did three easy oil-and-water experiments – or rather, explorations. I prefer this word because, honestly, I’m not really testing a hypothesis when I do a science demo for or with the kids. Just showing them cool stuff and asking what will happen. True, asking “what will happen if…” is perhaps the very essence of Doing Science. But I doubt many physics departments are concerning themselves with figuring out what happens if you stir oil and water with a fork. To me, if it’s not cutting-edge, and not likely to result in new knowledge for mankind, it’s an exploration.
Exploration #1: Stirring oil and water with a fork (not pictured). Glass of water, add oil. This is the oldest one in the book, but still, way cool. Stir and stir – you can barely get them to mix and a second later, they are separate again. Before I tried this, I actually demonstrated mixing water with juice – of course, they mixed perfectly in just a few seconds, so the oil thing is even more miraculous by contrast. Stir a few times; give each kid a chance to try to mix it – it’s hard. Then, add a couple of dots of dish soap and stir again. The soap is an emulsifier; it doesn’t dissolve the oil, but allows it to break down into millions of tiny dots, dispersed throughout the water, making the water look like very thick, opaque-y lemonade. Most of the oil rose out of the water again pretty quickly, but the water is still white-ish looking and the layer of oil on top is also white-ish and opaque. We can leave the glass overnight and see if the water is clear by morning.
Exploration #2: Ice cube in oil. Found this one on The Happy Scientist, but you can’t see it unless you have a subscription (I got a free subscription through The Homeschool Buyers Coop by referring good folks like you… so thanks!). I used a small glass to conserve oil, but then the ice cube didn’t really float freely – oops. No biggie, it was very cool how it hovered in the water, and I think that even though the Happy Scientist says the cube will float easily, that it was in fact less buoyant because the water wanted so badly to sink but the air bubbles in the ice cube were stopping it, so it sort of hovered in “mid-oil.” The cool part of the experiment is when the ice starts to melt – which it does almost right away. The water droplets are a thing of beauty, pulling down from the ice cube into the oil in an elongated teardrop shape and eventually breaking away to form what the kids described as “gold beads” on the bottom. Eventually, the beads do join up and just form a layer of water on the bottom, and I just poured off the oil for the next experiment when the ice cube was gone. Naomi asked, by the way, why the ice cube began melting right away even though the oil wasn’t hot. I pointed out that this probably happens when you put ice into a glass of water or juice, too, but you don’t notice because it mixes right away instead of forming the beads.
Exploration #3: Burn, baby, burn. This one’s a Happy Scientist experiment that you can actually read without a membership, because it’s on another site! I poured off the oil from Exploration #2 into an ordinary bowl. I took a piece of paper towel and showed them that if I set it on fire, it would burn up pretty quickly and be totally gone. Then, I crumpled another paper towel and set it in the bowl, giving it a minute or two to soak up the oil. This is actually what we do with little floating wicks every single night of Chanukah, because Ted and YM’s menorahs burn oil, but still – maybe they never looked closely before, and the little glass things don’t look like an ordinary cereal bowl, so it got their attention. I asked them what would happen if I set the paper towel on fire, and Naomi first said it would get burnt up, but then changed her answer – they probably know by now that if I’m asking them the question, there’s going to be a trick. Of course, as long as there’s enough oil in the bowl, the paper won’t burn up, but it was interesting to see how quickly the portion of the paper that hadn’t had a chance to wick any oil was consumed (almost instantly), while the rest was still going strong. I took the opportunity to demonstrate a second principle of fire by sliding a bowl over the fire, which put it out right away. I asked Naomi to guess why, and she semi-correctly guessed that it ran out of air (the truth is oxygen, as we learned with this Happy Scientist video on The Fire Diamond. (I don’t love The Happy Scientist, by the way, and probably wouldn’t have paid for the subscription, given the age of the kids, but I am pleased with everything we’ve seen so far and the kids seem to like it even if it’s a bit over their heads. I’m sure you can find many free videos explaining the principles of fire on YouTube.).
Exploration #4: Tea bag rocket. This one is all over the Internet (just google Tea Bag Rocket!), and it was in the science video I linked to last night. I tried it with Elisheva last night and we both thought it was amazing. You open up a tea bag (the kind that’s folded over and stapled at the top, NOT the plain cheap sealed-square kind) and empty out the tea. Stand it upright (borrowing a picture here, because I didn’t take any) on an ordinary plate (it won’t get scorched) and set the top on fire. The flame simultaneously a) consumes the teabag, turning it to ultra-lightweight ash, and b) heats and expands the cylinder of air inside the teabag. The upward force of the heated air is sufficient to lift the super-light ashy remains of the teabag, causing it to spontaneously “launch” from the plate and hopefully extinguish itself just before it reaches your ceiling. This is the same principle by which hot-air balloons are lifted off the ground… except, ideally, they’re not simultaneously turned to ash in the process.
Exploration #5: The flameproof balloon (Please! Read caution at the end!). Not exactly relevant to Chanukah, but while we’re burning stuff, this one was also in the video. Blow up a balloon and bring it close to a tealight. Even before it gets there, the balloon will pop from the heat (please read my caution note!). Now, fill another balloon with water, and bring it close to the flame. You should be able to bring it close enough to actually sit the balloon ON the tealight and put out the fire. This demonstrates the principle that the water quickly draws heat away from the plastic of the balloon, dissipating it harmlessly, so the balloon with water inside can survive at temperatures that the air-filled balloon cannot.
So here’s the warning I promised you: at the point that I demonstrated this, the tealight had been burning for a long time and was entirely melted, a puddle of wax with a wick in its little metal dish. For some reason which I am sure is exciting and scientific, at the moment the balloon burst, hot melted wax sprayed out for several feet in every direction (probably from the force of the air poofing out the hole in the balloon), splashing a couple of bystanders, though nobody was seriously hurt, and making a big mess of the table. If I was doing this again, I would a) make the kids stand farther back, and b) use a fresh, mostly-solid tealight which hadn’t been burning very long. I also recommend you name the balloons so the kids get attached to them and seriously mourn when “Mr. Balloon Volunteer #1” pops and dies. “Mr. Balloon Volunteer #2,” the one who survived, has been renamed Water Balloon Baby and removed to the tub for safekeeping.
In any event, this is practically a first for me. Because of practicing ahead of time, every single experiment – oops, I mean exploration – went off perfectly, so it was a great day of science. I even almost boiled water in a Dixie cup, another easily Google-able experiment. The only reason it didn’t work is that I was using a tealight as my heat source; most places recommend a bunsen burner, which I don’t have. It got surprisingly hot and there was even a bit of steam coming out, so I was pleased, call it a day, and proceeded to splash molten paraffin in every direction (see above).
But nobody was hurt! So yeah, successful Chanukah science.