Cool experiments with dry ice
Yesterday my wife and I did our latest kids science demo gig, at a holidays kid club at our church. My son has encouraged us to come up with some new demonstrations since some of the kids have already seen some of the old favourites, such as Elephants toothpaste , coke and mentos rocket , and a few others here . At first I was pretty excited when I saw this Youtube video of an LED powered by a lemon . Watch it and see what you think. I even got some LEDs to tried and do it. At the end of the post I tell the rest of the story. We settled on a few demos with dry ice [solid carbon dioxide]. The unique feature is that at atmospheric pressure the solid does not melt [become liquid] but sublimates [becomes vapour]. This is because in the phase diagram the pressure of the triple point [5 atm] is above atmospheric pressure. Here are some of the demonstrations. Many of them rely on the simple fact that the volume of one gram of vapour is of the order of five hundred times larger than th