I love it when you can combine science with a delicious edible treat.
So, I was excited to find a STEM activity that involved making ice cream in a bag. It seems like magic, but real science is happening inside the bag! The salt and ice create a solution that gets cold enough to freeze your milk.
The recipe below for ice cream in a bag makes two small servings. Want more? Double your ingredients.
This recipe makes vanilla ice cream, but add some powdered chocolate, and you will have chocolate ice cream! Experiment with other ingredients to create different flavors!
What You Need:
- 1 cup of any milk or half-and-half
- 2 Tablespoons sugar
- ½ teaspoon vanilla extract
- 3(ish) cups of ice
- ⅓ cup salt
- One sandwich-sized plastic resealable bag
- One gallon-sized plastic resealable bag
- Gloves
What You Do:
- Mix milk, sugar, and vanilla in the small bag. Squeeze out the air and seal.
- Mix ice and salt in the large plastic bag.
- Place the small bag into the big bag.
- Shake hard for 5-7 minutes or until the milk mixture is frozen. Use gloves because the bag will get very cold!
- Grab a spoon and enjoy!
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The Science Behind the Fun:
When salt comes into contact with ice, it lowers the ice's freezing point. Water will normally freeze at 32˚F. Ice cream needs to be frozen to less than 32˚F, and the salt makes that possible.
Try This: What happens if you add less salt, more salt, or no salt?
