On Sunday, while Athos was absorbed in NLB’s Tumblebooks and Aramis was having a nap, I had some rare one-on-one time with Porthos. I asked him what he wanted to do, and he said, “Let’s make a volcano.”
This is another inexpensive activity that the kids enjoy very much, though admittedly a little wasteful. Many websites explain how to build a volcano out of clay/soil/papier mache, then concoct a vinegar solution before adding in the powder. Given how quickly the experiment goes, I don’t find this a particularly good use of time, especially with impatient younger kids, so the process I describe is a whole lot simpler.
I use a large bowl, and put a small glass bottle in it – we have a saltshaker that works well. The smaller the better so you don’t use up too much vinegar at a go.
- Fill the bottle with vinegar. The cheapest option is artificial vinegar – Tai Hua brand costs $1.20 a bottle at NTUC.
- Add a few drops of food colouring for effect. Red or orange work best.
- Spoon in a bit of bicarbonate of soda, also available at NTUC for about $1.
Beyond the cool visual effect, you can also explain a couple of scientific points simply. First, mixing the two compounds releases carbon dioxide. That is what causes the ‘eruption’ and the bubbling over. Second, you can let the kids put their finger in the vinegar before and after the experiment. The vinegar will feel much cooler to the touch. That’s because the reaction needs energy to happen, and it take up heat from the vinegar. Also known as an endothermic reaction.
Speaking of endothermic, I’m finding that both Athos and Porthos love long words (current favourites include “momentum” and “paleontologist”). They may not be able to say it right nor understand precisely what the words means. But I think they just find it cool, the same way anything that is Really Big or Very Gross is cool.