Ice Cream is a quintessential part of summer! But it also makes for a great (and delicious) science experiment…no fancy machine or cranking required!
This ‘recipe’ was adapted from Steve Spangler Science.
Here’s what you’ll need: 2 sandwich-sized baggies, 2 gallon-sized baggies, 1/2 cup half-&-half (or milk), 1 tablespoon sugar, 1/2 teaspoon vanilla, ice, 1/2 cup of rock salt, and winter gloves.
*You can print off the step-by-step instructions by downloading your own free copy of our Fascinating Science for Kids ebook.
1. Pour 1/2 cup of half-&-half or milk into one of your sandwich-sized baggies. We used milk and it worked wonderfully. Add 1 tablespoon sugar and 1/2 teaspoon of vanilla extract. Get all of the air out and then seal the bag. Place your filled bag into another sandwich-sized baggie and seal.
2. Put your double-bag inside of a gallon-sized baggie and add your ice and 1/2 cup of rock salt. Place this bag inside another gallon-sized bag (you will have 2 small bags and 1 large bag inside).
3. Have your child put on some winter gloves and start shaking!
Shake the bag for about 15-20 minutes, passing it around the various members of the family!
I put a dishcloth around the bag when it was Little Brother’s turn…he karate-chopped it more than anything, but it turned out just fine!
All done! Nice and soft, but still slightly solid!
Ready to be served! This only makes a serving of ice cream. If you want to double the recipe, you can (just use quart-sized baggies instead of sandwich-sized). Don’t attempt to do any more than doubling, though, or it will be too heavy for the child to carry when you add ice and rock salt.
Little Brother approved!
Definitely Big Brother approved! He was SUPER excited about how yummy “his” ice cream turned out!
The Science Behind It:
The salt lowers the temperature at which ice freezes, or raises the temperature at which it melts (which is why we use it on the roads in the winter). Instead of melting at 32 degree Fahrenheit (0 degrees Celsius), the rock salt causes the ice to melt at a temperature much lower, depending on how much salt you add. The more rock salt you use, the lower the temperature the ice will melt at. This creates an environment that the ice cream mixture can freeze below the normal 32 degrees. Then the salt/ice slush absorbs the heat from the cream mixture, lowering the temp of the cream and causing the cream to ‘ice’, creating the yummy ice cream texture!
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We used to do this as kids when we spent the night at our grandparents house – except we used 2 coffee cans. Put a small can with the ice cream ingredients in the large can with salt/ice and then us kids would sit on the floor and roll it back and forth between us! Thanks for the recipe, I’ll have to do it this summer with my littles!
I’ve tried this, too, and it really works. Kids love it!! I’ll try the coffee can method – rolling it seems like fun. The bags do get super cold, so don’t forget the gloves. But kids love wearing gloves in the summer! Thanks for reminding me about this fun activity. Renee
My 4 year old son said “This is the better than the real stuff”! Ha! How said that he doesn’t know this IS the real stuff. : )
May I ask what font you used for the words “ice-cream” ? Love it, and can’t find it anywhere….
Thanks for your fun posts/blog!
It is a font I used on the online photo editor I used for this particular collage called ipiccy.com . Looks like it is called Deftone Stylus. :)
We made this last year – what a simple way to get some quick ice cream. Of course I love my Cuisinart electric ice cream maker but I love that my daughter could actually make the ice cream in a bag herself. It did taste good too!
Does anyone know if this would work with coconut milk? Thanks!
Thank you!!!So excited to do many of these things this summer!!!!!
Would this work with soy milk ?
yes you can use soy milk for this recipe and boy is it delicious
Hi! Thanks for your fun post, with pics of the kiddos, too! Glad to see that you are doing such a great job of inspiring folks to explore kid-friendly & tasty science! Just wanted to clarify the ‘science’ listed on your post though–I think that you meant to have “freeze” instead of “melt” (the salt lowers the temperature at which the ice freezes, or raises the temperature at which it melts :) ). Then the salt/ice slush absorbs the heat from the cream mixture, lowering the temp of the cream and causing the cream to ‘ice’, creating the yummy icecream texture!
Thanks for the clarification, Lisa! I must have missed that in my proofreading. :)
And I added your last sentence as well. A great addition to the explanation! Thanks!
VERY SALTY. It still O.K., but don’t suggest doing half a cup of salt( little bit too much).
Did you add the salt to the cream mixture or to the ice? My understanding is that your ice cream shouldn’t have any salt in it at all!!!
Yes, the salt is to be mixed in with the ice…not in the mixture itself. Sorry if that is confusing! :)
What kind and where did you find the correct rock salt for the Ice Cream In A Bag?