Ice cream in a can, teaching science

This summer, our hill at the lake will be used in yet another ingenious way: to make ice cream for our root beer floats. I was tempted to buy the traditional ice cream maker, but there are so many choices; I quickly became overwhelmed looking at all the bells and whistles. And besides, I have all that boy power just dying to get put to use. Plus, the process of making ice cream by hand… literally…. in the can… is is a great way to introduce some lessons in science. There is the ice cream in a bag method; my boys would surely break the bag in the mixing process. So, I’ve decided to go with the ice cream in a can method.

  1. The first challenge is finding the can. Many recipes suggest using a coffee can, but who buys coffee in a can anymore? A better idea is to ask for an empty paint can from the paint store. You’ll need two: A quart, and a gallon.
  2. Ask your kids to tell you the freezing point of water — or teach them — 32 degrees F, or 0 Celcius. Then, ask them what happens when we put salt on icy sidewalks. Ask them to start thinking about why we need salt to make ice cream.
  3. In the small, clean can, add one cup of milk or half and half, one cup of sugar, and one teaspoon of vanilla.
  4. Optional: add one tablespoon of chocolate syrup — or frozen strawberries.
  5. Use a hammer to seal the lid tightly.
  6. In the larger can, combine the ice and rock salt. Use a thermometer to record the temperature of the rock and salt mixture.
  7. Use hammer again to seal the lid tightly.
  8. Take turns rolling the can down the hill, for about five minutes. This will “solidify” the ice cream.
  9. Explain what’s happening: the ice melts and combines with the salt. This “brine” has a lower freezing point — lower than 32 degrees.
  10. After five minutes of rolling, open the large can, and take the temperature of the ice. It will be colder than it was the first time.
  11. Open the smaller can. The colder brine was able to get the milk mixture cold enough to freeze to a solid, to create ice cream.
  12. You know you’re going to have to whip up another batch right now; the fun was really rolling the can down the hill.
  13. An instant way to eliminate the ice cream headache is to put your tongue on the roof of your mouth. Teaching a toddler how to do this is something you won’t soon forget.

Pictures to come…
Thursday Thirteen

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35 comments to “Ice cream in a can, teaching science”
  1. Wow! That’s so cool! I can’t wait to store this away to do with my son when he is old enough. I LOVE homemade ice cream and this has to be the most fun way to do it!

    Thanks so much for sharing.

    Happy TT!

  2. You are an amazingly industrious woman. I look forward to coming here because I never know what’s going to be here. And it’s always helpful. (Although we’re off dairy for a while… long story!)

    Happy TT!

  3. I love making ice cream but never could get my family motivated enough to do it more than once. Maybe if I had started it off when they were the age of your boys it would be a family tradition by now. It still sounds like great fun to me.

  4. Discovering your blog for the first time thanks to Susan Helene Gottfried who left me a comment about your post. This is a great post and I would love to have you participate in my Ice Cream Recipe Round Up in July. Come by to see all the details. This week’s Thursday 13 is also pictures of ice cream sundaes.

    Love your blog. I’ll be back. 🙂

  5. I love how you can make any recipe into exactly 13 steps to fit your TT! You were reading my mind with the paint can idea, and I bet kids think it’s great fun to use the hammer. (Thanks for visiting my TT)

  6. We have an ice cream maker so my kids never learned the salt bit. I think I’ll tell them about that time at the lake (we used to spend every 4th of July at friends’ lake house) where the canister had a hole in it and all that wonderful strawberry ice cream came out salty!

  7. I love to make homemade ice cream! We use the Play and Freeze Ice Cream Maker; I ordered it from Steve Spangler Science and it’s fantastic.

    I have a small strawberry patch and when you unscrew the lid to the can and drop in a few handfuls of strawberries and then finished shaking it up, it’s so good. . . . well, now I have to go make some! I made myself drool!

    I got my ice cream maker here:

  8. i’d never heard of this method. and it takes only five minutes?
    when we were kids we made it one with a hand crank and us kids took turns cranking. it took over 30. but we were making a gallon. maybe that is the difference?

  9. I never could completely understand why ice needed to be combined with SALT. Now, it’s clear from your explanation of a lower freeing point. Thanks for an interesting TT! Have a good time by the lake, too.

  10. Pingback: Exactly HOW MUCH ice and salt | Susiej

  11. This is such a fantastic idea. Your website was passed onto me from a friend so I hope you don’t mind that I added a link to this post on my ice-cream party blog post.

  12. Pingback: Ice Cream in a Can, Teaching Science | Blog Nosh Magazine

  13. I was wondering if there was a specific amount of rock salt that should be added to the ice and also if you think milk or the half and half tastes/works better? Thank you!

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