What’s better than ice cream on a hot summer’s day?! Ice cream with a little kids’ science sprinkled on top, that’s what! This deliciously fun ice cream in a bag is so simple. It’s one of our favorite treats to make while camping.
With a few common ingredients and a little muscle, you too can enjoy delicious homemade ice cream in a bag! For more science fun, check out our 30 Science Experiments your kids will beg to repeat!
For one serving of ice cream, you will need:
- 1/2 a cup of half and half, cream, or milk
- 1 tablespoon of sugar
- 1/4 teaspoon of vanilla
You will also need:
- 2 sandwich or quart-sized baggies
- gallon sized baggie
- 1/2 cups of salt (larger salt like rock salt works best)
- ice (around 5 cups)
- gloves or small towel (optional)
Making Ice Cream in a Bag
First, I handed each kiddo a sandwich sized bag and had them measure out the sugar and vanilla.
Next, they measured a half cup of half and half and carefully added this to their bag.
I helped them squeeze out most of the air and seal the baggie really well. They placed the baggie with cream into another sandwich bag for added protection. We’ve done this before with just a single small bag and the salt water leaked into the baggie making the ice cream a wee bit salty.
Next, we placed the doubled up sandwich bags into the larger gallon baggie and added about 5 cups of ice.
Finally, we added the 1/2 cup of salt to the ice and sealed the baggie. We ran out of rock salt and used kosher salt instead – the experiment still worked fine. Now all that was left to do was shake!
After about 5 minutes the cream began to feel slightly thicker. My 5 year-old, A, just had to remove the sandwich baggie to check on its progress. By this point, the kids were getting pretty tired so it was my turn to shake. I added another handful of ice, resealed the bag, and shook like mad. After several minutes we had ice cream!
The easiest and least messy way to get the ice cream out was to cut off a corner of the sandwich bag and squeeze out the cream like soft serve.
And what is ice cream without sprinkles?!
Yum! Science sure is tasty!
The Science Behind Ice Cream
The salt you add to the ice causes it to start melting, just as salt added to icy roads does in winter. Normally water freezes at 32 degrees F (0 degrees Celsius) but when salt touches the ice, it lowers the freezing point to much lower than that. The more salt, the lower the temperature ice will melt.
In order for the ice to melt, however, it has to absorb heat. The heat that it absorbs comes from what’s around it. In this case, it takes heat from the air and the warmer cream mixture. The icy salt water solution becomes colder than 32 degrees F by sucking heat from the cream and this allows the cream to freeze. Remember, the cream doesn’t have salt in it so it will still freeze at 32 degrees F and that’s good news for you!
Check out our awesome stash of 30 Science Experiments in our shop to keep the science fun going all year!