Liquid Nitrogen Ice Cream

This is a chemistry project that my husband and his college students do in the elementary schools each year. Kids of all ages love it. Our neighbor, Emilee, was absent the day my husband came to her class. So, today, he brought home the ingredients and we invited her (and a few other neighborhood kiddos) over to make ice cream!

The nice thing about being married to a chemist is that he has access to cool stuff. One of the coolest is liquid nitrogen. Not only can you burn off your own warts, you can also dip stuff into it (like this hydrangea blossom) and then SMASH it on the counter. The liquid nitrogen hardens the flower, causing it to shatter upon impact. The kids (and grownups!) love this.


But liquid nitrogen is also great for speeding up the process of making homemade ice cream! Yes...you can make it in minutes!!

The recipe is a little rough. Basically, it's an eyeball recipe. If you don't have enough of one thing, you add a little more.

Ingredients:

-Liquid Nitrogen (welding places can be a good source for this)
-styrofoam cups
-plastic spoons
-milk (we used skim)
-vanilla w/sugar or vanilla syrup (like you'd put in coffee)

First we gave each child two 8 oz. styrofoam cups and a spoon. They doubled up their cups (better insulation). Then we poured milk in each cup, filling it about halfway. Next we put in a few (3-4) squirts of vanilla syrup.

While the kids mixed this together, Brian poured some of the liquid nitrogen into another cup. From this cup, he poured a little into each of the kids' cups. The kids stirred and stirred, scraping the sides continuously.

If it's too liquidy, add a little more liquid nitrogen. Keep stirring!!

Once it gets to a slushy state, and the liquid nitrogen has evaporated, you can taste it to see if it's to your liking. (I added more vanilla syrup at this point!)

One of the best things about this, is it's easy, fun, and soooooo cool when the condensed water from the liquid nitrogen surrounds you!

Safety Tips: Have a grown up handle the pouring of the liquid nitrogen. Don't allow it to touch skin. Remember when I mentioned it's used to burn off warts? Well, that's because liquid nitrogen is cold enough to burn skin. So keep it away from skin! Also, make sure the liquid nitrogen has completely evaporated before eating.