Ziploc Baggie Ice Cream

Today was my day to host our home(pre)school group. My intention was for the kids to play in the park's splash pad, make our own ice cream, and read "Summer" from Arnold Lobel's Frog and Toad All Year (in which Toad buys Frog and himself chocolate ice cream cones but winds up with the ice cream - and sticks and leaves - all over him).

Toad as an ice cream "thing"

We did not get around to the story, but the ice cream was a success!

If you haven't done this, DO. Here's how:
1)Get two sandwich sized Ziploc baggies and put one inside the other. (I recommend double-bagging so salt doesn't get on the baggie with the ice cream in it, or so as little salt as possible gets on the ice cream baggie.)
2)Put 1/2 cup of milk in the inner baggie. (I've done this with both 1 percent and whole milk. You can also do this with heavy cream or half and half, and I'm guessing nonfat would work too. It just depends how rich you want to make your ice cream.)
3)Add 1 tablespoon of sugar and 1/4 teaspoon of vanilla extract.
4)Put the sandwich sized baggies inside a gallon Ziploc.
5)Put 6 tablespoons of salt in the bag and cover the "ice cream" with ice cubes. (One recipe said 4 cups, but the important thing is to cover the "ice cream." Also, I've done this with both sea salt and rock salt, and both work. Any salt will work, but recipes recommend larger crystals.)
6)Put on your oven mitts (or mittens, or socks on your hands - it gets REALLY cold) and shake until the ice cream solidifies. Some recipes say five minutes. One try, I shook for exactly 6 1/2 minutes and that worked (I watched the stopwatch on my phone). The important thing is to shake until the ice cream feels really hard. (The salt will turn the ice into brine and saltwater will drip out of the bag, so doing this outside is a really good idea.)
7)Take the sandwich-sized baggies out. If you have ice water nearby to rinse the outer baggie, do. If not, it's okay. Carefully take out the inner baggie. You'll taste a tiny bit of salt, but the ice cream will still be good; one mom suggested adding a tiny bit of caramel sauce to the inner baggie for a "salted caramel" treat -Yum.
8)You can add a small amount of chocolate sauce or strawberry topping (or caramel sauce), or any other mix-in to the baggie, seal, and give it an extra couple of squishes.
9)Squeeze the ice cream into a waffle cone. Top with sprinkles (or your favorite topping). Enjoy.

(This makes one serving.)

The average freezing point (also called the melting point) of milk is -.54 degrees Celsius (which is 31.028 degrees Fahrenheit). The freezing point of milk is just a tiny bit lower than the freezing point of water (0 degrees Celsius/32 degrees Fahrenheit), so you need salt's help. Salt lowers the temperature. For a chemistry lesson on why salt lowers the freezing point of water (including an animation) click here.