For our science lessons, we’ve been learning about some of the physical processes involved when gasses and liquids are heated up (or cooled down).

We measured a balloon filled with air, then measured again when we heated it over the furnace vent for an hour or so, then put it in the fridge for an hour and measured it again tp learn that when air is heated it expands, and when it is cooled it contracts.

We also tried some experiments to demonstrate the movement of hot and cold air. The most fun was the Warm Air Whizzer (from The Best of WonderScience)

On a piece of cardstock, we traced around the lip of a coffee mug to get a perfect circle. Then we fold it in half three times to get folds that look roughly like the image below.

We measured and cut 2cm slits down each of the folds, and folded the left side of each “pie piece” down and the right side up. Then we poked a hole in the center, and hung it from a knotted piece of string.

Then all we had to do was find a heat source. Sadly, we have over-greened our home, and we couldn’t find a light bulb that generated enough heat to spin our whizzer. They did quite adequately illustrate that it was NOT light that spun the whizzer, however. In the end we used a candle to demonstrate the air movement, and it worked rather well.

We spent several hours experimenting with the whizzer… getting it to spin the other way, trying to get it to spin using cold air above it, and using magnifying glasses and mirrors to see if we could get it to spin using solar energy.