I’ve done this edible science experiment – making lemon sorbet – with my daughter’s Girl Scout troop and for my son’s classroom birthday celebration, and it was a hit both times. Seeing as how we’re now in the dog days of summer, I figured it’d be the perfect thing to share. It’s a fun way to cool down on a hot afternoon.
All you need is some lemonade, crushed ice, table salt, and Ziplock bags (one gallon size, one sandwich size).
Pour the lemonade into the smaller Ziplock bag (you can prop up the bag in a cup, if it helps). Squeeze out the excess air, and seal up the bag. You can double bag it if you’d like, just to be safe.
Place the juice bag into the larger gallon size bag, and pour in the crushed ice so it’s surrounding the closed juice bag. Then pour salt liberally all over the ice (at least four tablespoons worth). Seal up the gallon bag (double bag this, too, if you’d like), then have your kids take turns massaging the bag gently, so the ice is constantly coming into contact with the juice bag. In about five minutes, the juice will have turned into sorbet!
I’m probably not the best person to explain what’s going on here, but from what I understand, the salt is lowering the freezing point of the ice, causing it to seek heat from the juice – and turning it into a frozen treat in the process!