Is it hot where you live in the summer? What if I gave you a recipe for making ice cream that doesn’t require an expensive ice cream maker, hours of churning, and can be made to any flavor you can dream up? (Even dairy-free if needed?)
If you’ve got a backyard full of busy kids that seem to constantly be in motion, then this is the project for you. The best part is, you don’t have to do any of the churning work… the kids will handle it all for you!
This experiment is simple to set up (it only requires a trip to the grocery store), quick to implement, and all you need to do guard the back door armed with a hose to douse the kids before they tramp back into the house afterward.
One of the secrets to making great ice cream quickly is [am4show have=’p8;p9;p23;p50;p80;p88;p101;’ guest_error=’Guest error message’ user_error=’User error message’ ] to be sure that the milk and cream is COLD. I will make this particular recipe, it’s usually with hundreds of kids, and our staff will stuff the milk products in the freezer for an hour or two or under hundreds of pounds of ice to make sure it’s super-cold.
If you’re going for the dairy-free kind, simply skip the milk and cream and add a bit of extra time to the chill time of your substitute ‘milk’. We’ve had the best luck with almond and soy milk. Are you ready?
Here’s what you need:
Materials:
- 1 quart whole milk (do not substitute, unless your child has a milk allergy, then use soy or almond milk)
- 1 pint heavy cream (do not substitute, unless your child has a milk allergy, then skip)
- 1 cup sugar (or other sweetener)
- 1 tsp vanilla (use non-alcohol kind)
- rock salt (use table salt if you can’t find it)
- lots of ice
- freezer-grade zipper-style bags (you’ll need quart and gallon sizes)
Download Student Worksheet & Exercises
How does that work? Ice cream is basically “fluffy milk”. You need to whip in a lot of air into the milk fat to get the fluffy pockets that make this stuff worthwhile. The more the kids shake the bag, the faster it will turn into ice cream.
Why do we put salt on the ice?
If you live in an area where they put salt on the roads, you already know that people do this to melt the ice. But how does salt melt ice? Think about the chemistry of what’s going on. Water normally freezes at zero degrees Celsius. But salt water presses lower than zero, so the freezing point of salt water is lower than fresh water. By sprinkling salt on the roads, you’re lowering the point at which water freezes at. When you add a solute (salt) to the solvent (water) to alter the freezing point of the solution, it’s known as the “freezing point depression”.
Tips: Don’t use nonfat milk – it won’t work with this style of ice-cream making. if you’re adding fruit or chocolate bits, make sure you get those cold in advance too, or they will slow down your process as they heat your milk solution. (We usually add those bits last after the ice cream is done.)
IMPORTANT: Do NOT substitute dry ice for the water ice – the carbon dioxide gases build quickly and explode the bag, and now you have flying bits of dry ice that will burn skin upon contact. That’s not the biggest issue, though… the real problem is that now animals (like your dog) and small children pop a random piece of dry ice into their mouths, which will earn your family a visit to the ER. So stick with the regular ice from your fridge.
[/am4show]
That’s a stock picture but it does look delicious, doesn’t it!
Is the ice cream on the last slide of the video the ice cream that you have made or just a picture online? It looks REALLY delicious!!! If you did make that, then I hope mine turns out as amazing as yours! I’m thinking of putting frozen blueberries or strawberries.
Yes, you should have access to this ice cream experiment. I’ll have Tonya connect with you to check to see if your account is set up correctly.
ALso, find the liquid nitrogen video here on this page:
https://www.sciencelearningspace2.com/science-with-aurora/spring-break-camp
Hello, is there a way to access your Football Ice Cream (Liquid Nitrogen Ice Cream)? You mentioned it in today’s class and my sons are very interested in making it.
Thank you,
Lisa
Can you make this with half and half instead of heavy cream?
You should be able to access it at this link once you’ve logged in:
http://sciencelearningspace2.com/standardcontent/docs/ecamp-Football-Ice-Cream.pdf
Does that work?
Can we get the student worksheet please??
Of course!
can you use coco powder
My son had a lot of fun making this. And the ice cream tasted delicious!
Hey Aurora loved your recipe for the ice cream at first I shook it around and tried some of the ice cream but it was still just frothy then I accidentally left it in the freezer and then I found it the next morning and it was hard then thawed it a little bit and it tasted great
I hope I can make it
It does if you let the kids have it… 🙂 Try to find alcohol-free vanilla or add a different flavoring for the one you let the kids eat.
hmmm, I love my real vanilla extract. I make it myself…in vodka…does the alcohol change anything? Just wondering….
Of course! Just add in flavor when you mix it (like chocolate syrup) or mix-ins afterwards (like candy or nuts).
Is there any way we can make our ice cream a different flavor?
It sounds like your mixture didn’t get cold enough. Did you use rock salt?
Try it again, but chill the milks in the fridge (or freezer for 20 minutes) just prior to using it. You want them really cold first.
My ice cream turned into kind of a soup, even though I had all the ingredients stored in the freezer, and shook it for about 20 minutes. Did I over shake it? What did I do wrong?
Heavy cream works better, but you can even omit the cream as long as you get the milk REALLY cold first.
Do I have to use heavy cream or can I use light cream?
yum!
Since I don’t like overly sweet things, that’s the way I make it when I whip up a batch for myself as it’s fine for my taste buds, but you might want to make a small batch to see how it tastes to you, since cocoa powder can be pretty bitter. 🙂
Aurora,
Is there enough sugar in the ice cream to use unsweetened cocoa powder for chocolate ice cream?
Thanks, Isabel
So glad it worked for you!!!
I made up most the ones on e-Science, and the rest came from years of teaching kids in the classroom. Rarely do any come off the internet (I can’t even think of one…) If you see a duplicate, it is possible we had the same inspiration. 🙂
Hi Aurora, I made the ice cream 😀 I haven’t ate any yet but I have a feeling it will be good because I worked so hard!
First thing, I live in Canada so its cold.
Second thing, I started shaking outside and I had no shoes or socks or mittens 😛
Third thing, I came in numb head to toe even though I had a coat on. (0 degrees outside)
Took about 10 min of shaking and it turned into a slushy hard, I put it in the freezer to cool!
I had lots of fun making it 🙂 Also I have a question. Do you make all these experiments, or do you get them of the Internet?
Thanks
Raena
Yes, anything COLD will work. Ice, snow, etc. If you add salt to it, the ice and snow will in effect get ‘colder’ and your milk mixture will turn into ice cream much faster. 🙂 Let me know how it goes!!
Hi Aurora, I want to do this so much but…. I need some help 🙁 How do you make so much ice….or can I use snow? 😀
I really like this program and all your hard work!
Thanks so much
Raena 😛
The salt breaks apart and bonds with the water molecules by getting in the strong hydrogen bonds. This lowers the freezing point as it is no longer “pure ice”. When you add more salt, the freezing point goes down further for the ice.
Salt melts wet ice because when salt lowers the freezing point of the water. Ice is usually coated with a thin film of liquid water, which is why this works. If you toss salt onto ice when it’s frozen solid without a liquid layer on top, the salt will form a layer on top the ice and stay put. However, if you put salt on ice at a slightly warmer temperature, the salt will prevent the melting ice from refreezing.
The amount of heat the ice gained as it melted is no longer the same as the heat given up from the water freezing because the water doesn’t refreeze, so the heat gained came from somewhere else.. the sidewalk.
How does salt make the sidewalk colder? Doesn’t it just cause the ice to melt because the salty ice now needs a lower temperature to stay frozen?
When ice melts, the temperature is 0 degrees Celsius (32 degrees Fahrenheit). Ice gets wet when it welts, which means that there is ice (a solid) on one side and water (a liquid) on the other. Some of the liquid water refreezes into ice, and some of the ice melts into water. Scientists call this ‘equilibrium’ when the rate of melting and freezing are the same. For our case, this happens at 0 degrees Celsius.
Our ice cream needs to freeze at a temperature lower than this, so we have to add salt to lower the freezing point. Salt water freezes at a lower temperature than plain water. Ice-salt has a freezing point of -21 degrees Celsius (-6 degrees Fahrenheit), which is 21 degrees Celsius (40 degrees Fahrenheit) colder than ice.
Putting salt on an icy road means that the sidewalk gets colder than it was before. If you add calcium chloride instead of salt to an icy road, you’ll get an even lower freezing temperature of -29 degrees Celsius, or -20 degrees Fahrenheit.
Isn’t chemistry cool?
Why do you need salt? What does the salt do?
I hope i can make it
We followed Aurora’s video and it worked great for us. We had lots of fun. Our youngest had the quote of the day:
“I like my science with sprinkles”
Ms.Aurora, my family has a recipe for homemade ice cream and i would like very much to share it with you and this is what we do:
ICE CREAM MIX
2c. of eagle brand milk
2c.water
about 3c. homogenized milk
1-2t. flavoring
1 large can of evaporated milk
3/4c. sugar
(fruit if desired)
Mix all ingredients well & place in freezer & and freeze. And that is all we do. Thanks for your way of making Homemade Ice Cream.