That's two close answers.
I was simmering some water and Fairy liquid to thoroughly clean out a few stuck on bits in my non-stick electric skillet. (Square frying pan, effectively.) Normally it cleans out with a plastic scraper and a wipe around, but occasionally I give it the full treatment.
The square element underneath the centre created a squarish pattern to the bubbles.
I took a short video as well to show Alma, because the bubbles show the convection currents in action. On the right you can see the cooler water 'falling' back into the centre between the gap in the element before the heat spreads it outwards again.
Convection, being generally invisible, is something you normally have to take on trust. So a chance to see it in action was worth capturing for my little science monster. She'll love it ;-)
Gyppo
