Channel your child’s inner Elsa and help them grow their own ice.
You will need: room temperature bottled waters in a plastic bottles, freeze as many bottles as you want (distilled or purified works best; do NOT use a glass bottle), food colouring (optional), wide-mouth cups, ice cubes, tray with sides (like a baking sheet) or large shallow dish.
Watch the video tutorial below.
Begin by placing the water bottles in the freezer on their sides for approximately 2 hours and 45 minutes (depending on your freezer, it may take more or less time). If you choose to add one or two drops of food colouring to your water, now is the time to do so.
The purpose of putting the bottles in the freezer is to get the water to an extremely cold temperature, which makes the ice formation possible.
If your bottles start to freeze, just take them out, let them return to room temperature and start again and keep them in the freezer for 15 minutes less. (If ice doesn’t start to grow when you begin pouring your water over the ice in the cup, your water is not cold enough, and you will need to return the bottles to the freezer for another 15 minutes or so.)
When your water has been sitting long enough, and is free of any ice, CAREFULLY remove it from the freezer. Be careful not to bump, bang, or drop the water bottle or the whole bottle may freeze into a solid block of ice instantly. Place a couple of ice cubes into a wide-mouth cup.
Begin slowly and carefully pouring the cold water over the ice. You should notice a mound of slushy ice forming on top of the ice cubes in your cup.