Background chemistry, freezing, phases of matter, solutions, freezing point depression. One way to do this is by using salt. Kids can help shake the bags and of course finish off the ice cream. Chemistry of Ice Cream–Making: Lowering the Freezing Point of Water, from Science Buddies, This activity brought to you in partnership with Science Buddies, 16 minutes ago — Jennifer Frazer | Opinion, November 11, 2020 — Dhananjay Khadilkar, 17 hours ago — David Cyranoski and Nature magazine, 18 hours ago — Daniel Cusick and E&E News. Paper Roller Coasters - Fun STEM Activity! Ice Cream in a Bag Ingredients. You should have seen that the ice cubes in the large bag with salt melted much more, and felt much colder, than the ice cubes in the large bag without salt. In a quart-sized (regular) ziploc plastic bag, mix together the milk, sugar, and vanilla. Now add four cups of ice cubes to the other large, gallon-sized bag, but this time do not add any salt to it. Feel free to mess around with this one- maybe sneak a little malted milk in the mix, or a little chocolate syrup. Salt. water normally freezes at 0℃, a 10% salt solution freezes at -7℃ and a 20% solution freezes at -17℃). Discover world-changing science. A lot of interesting chemistry is actually needed to make ice cream. 12 %, (Or any kind of milk, I always have 1% in the house), (Whatever kind of salt you have on hand works fine). Please enter a search term in the text box.   When a freezing point is lowered, such as by adding salt to water, the process is called freezing-point depression. Explore our digital archive back to 1845, including articles by more than 150 Nobel Prize winners. If you want the ice cream to be more firm, feel free to throw the bag into the freezer for a little while. Remove the inside bag (maybe even rinse off the salt) and you can either eat the ice cream right out of the bag with a spoon, or pour it into a small dish. All rights reserved. When printing this document, you may NOT modify it in any way. If the ingredients in one of your bags did not become ice cream, check out the extras below for tips on turning them into ice cream. (If you are a little paranoid about it leaking out, feel free to tape it up!). Curious about the science?Post your question for our scientists. Feel the smaller bag every couple of minutes while you shake it and take a peek at it. How do the ingredients change during this process? Half-and-half. Put one of the small bags you prepared into the large bag with the ice cubes. Technically, the temperature that the salt lowers is called the freezing point. Introduction Boiling-Point Elevation and Freezing-Point Depression, from Iowa State University It's is not exactly gourmet ice cream or anything, but it's tasty! Put the small bag into the large bag, add the ice and sprinkle all of the salt over the ice. And if you’re low on ice cream in your freezer, it’s a great way to make your own treat! Shake, mush, and squish the bag for 6-10 minutes, or until the ice cream has set to a soft serve consistency. Now mash the bag for about 10 minutes until you can see that the milk has turned to ice cream. Then add one half cup of salt to the bag. Again, feel the smaller bag every couple of minutes while you shake it, and take a peek at it. Be sure both bags are sealed. Different types of salts, such as table salt or rock salt, will all work, but may give slightly different results. You only need 5 ingredients to make ice cream in a bag: In a gallon-sized ziploc plastic bag, mix the ice and salt. This is perhaps the easiest ice cream recipe out there! You can find this page online at: How to Make Ice Cream in a Bag. Put on oven mitts or wrap the bag in a small towel and then shake the bag for five minutes, as you did before. In each small bag, place one tablespoon of sugar, one half cup of half and half (or milk or heavy whipping cream) and one quarter teaspoon of vanilla extract. The ice–salt combination gets colder than pure water ice and can freeze the ingredients in the ice cream machine (and in the bags you used in this activity), turning them into ice cream. For any other use, please contact Science Buddies. For example, think about how you start out with refrigerated (or even room-temperature) ingredients and then need to cool them down to turn them turn into ice cream.