Well we came up with it and had a lot of fun playing with our Magic Jello Ice Stars. They are simple to make and super fun.
All you need to do is mix about 3 tsp of jello with 1/2 cup of hot water, once the jello is dissolved then mix with about 1-2 cups of baking soda. Don't make it too thick you want it a little runny to pour into the ice trays. (We got our start ice trays from Dollar Tree)
Then let it freeze and you have your magic jello ice.
Place on a tray and make them erupt and bubble with vinegar. Once the vinegar dissolve them you will have a goop like sensory play.
NOTE: You can make them with Kool-Aid as well.
This is a fun experiment for all ages.
We love ice play be sure to check out some other fun ice things we have done.
Alphabet ice learning
Dinosaur ice excavation