If you want to get the kids outside, give them a good workout and teach them a little bit about science - all while having a ton of fun – Making Ice Cream Outdoors is the family activity for you!

You may end up with some ice cream, or you may end up with something a bit more like a milk shake, either way don’t be afraid to refine the process and try to make it better. That’s what science is all about!

What You’ll Need to Make Ice Cream Outside

• 2 Cups of Heavy Cream
• 2 Cups of Whole Milk
• 3/4 Cup of White Sugar
• 4 Tablespoons of Vanilla Extract
• Empty, Metal Coffee Can with its Plastic Lid (thoroughly cleaned) or a similarly sized plastic container. Our can held 34.5 ounces of coffee in it.
• 5 Gallon Plastic Bucket with Lid
• Duct Tape (packing tape will do in a pinch)
• Large Bag of Ice, smaller cubes work better than larger ones (enough to fill the bucket when the can is inside)
• 1 – 1 1/2 Cups of Coarse Salt (Kosher salt or sea salt)
• 2 Cups of Water
• Watch or clock
• Ladle to scoop out the ice cream

The Process for Making Ice Cream Outdoors

1. Mix your heavy cream, whole milk, white sugar and vanilla extract together in the coffee can. Basically, the mixture should fill up the can about half way, not more.

2. Put the lid on the coffee can and seal it up nice and tight with the duct tape.

3. Put a few inches of ice in the bottom of the big plastic bucket. Place the coffee can inside on top of the this ice.

4. Mix the 1 cup or so of coarse salt in with the 2 cups of water, stirring until it’s as mixed as mixed as it will get. Pour half over the ice cubes you have in the bucket. Fill the bucket with ice so it is even with the top of the can and pour in the rest of the salt water. Then fill the bucket to the top with ice.

5. Put the lid on the bucket and seal it up nice and tight with the duct tape.

6. Time for some exercise! The kids have to shake, roll, kick, twist and turn the bucket VIGOROUSLY for at least 15 minutes. Energetic music might be a nice touch. Personally, I drove them like a drill sergeant. (Hint: use a watch to time it. It seems like 15 minutes has gone by when it’s only been about 5 minutes.)

7. Open up the bucket, remove the can, wiping off and excess water and whatnot from the bucket. (You don’t want to get the salt water inside your ice cream.) On inner side of the can, you find a layer of frozen ice cream that you want to stir quickly into inner liquid.

The colder you got it the more like ice cream it will be. Worse case scenario, you have a tasty milk shake.

Outdoor Ice Cream Science

Condensation. As you are making the ice cream you notice that the big plastic bucket will get an ice patina over much of its surface. This is caused by condensation. Simply explained, water vapor in the warm air, turns back into liquid and then ice when it touches the cold plastic bucket.

Thermal Conductivity or Conductance. Simply put, this is the quantity of heat that passes through the can. We chose a metal can, because metals are good thermal conductors. A good question to ask your kids is which direction are we trying to move the heat in order to transform our mixture into ice cream? (From within the coffee can where it is warmer to the bucket where it is colder.)

Chemistry of Salt. The entire process here relies on salt and water. The salt water and the friction from the rocking of the bucket create more and more water in the bucket. The salt lowers the freezing point of water, allowing it to remain liquid at temperatures below 32 F or 0 C.

This allows the water to act as a more efficient cooling agent than the ice alone, since more of it’s surface area can be in contact with the can’s surface. As the can cools, the ice cream mixture also begins to freeze.

The jostling of the bucket serves one other purpose. It churns the ice cream, keeping it from forming ice crystals, so you end up with a creamy product.

That’s all there is to it! It’s fast, easy and lots of fun for everyone involved! And the kids might even learn something in the process.