Liquid Nitrogen Ice Cream
Standards:
SC.03.31.01.03 Matter exists in different states such as solids, liquids, and gases and can change from one state to
another by heating and cooling (CAS: 3.1.1)
Materials:
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Liquid Nitrogen (5 liters)
Safety gloves
Safety glasses
1 quart half and half
1 pint milk
3 tbsp. vanilla
½ cup sugar
Stainless steel mixing bowl
Wooden mixing spoon
Plastic sheet to cover table (I used plastic wrap)
Objective:
This lesson is meant to teach students about boiling points and changes in states of matter. This lesson
goes well after lessons on boiling using boiling water as a demonstration. It also introduces students to
the idea that different substances have different boiling points. Along with teaching about boiling
points, this lesson also gets students excited about science since it is very exciting to watch.
Set Up:
Prior to beginning the lesson, have all of the necessary ingredients set up and have the plastic wrap over
the table. Additionally the necessary safety precautions should be stressed to the students. Explain that
they will not be able to directly interact with the liquid nitrogen because it is very dangerous if not
handled properly and it will burn you if it comes in direct contact with your skin.
Instructions:
Begin by explaining to students that liquid nitrogen boils at −321° 𝐹 or−196° 𝐶. Make a comparison
between this and water boiling. Have a discussion about what they think will happen because liquid
nitrogen has such a low boiling point; ask what they think will happen when the liquid nitrogen becomes
room temperature. I also like to talk about how liquid nitrogen can be used to flash freeze foods before
beginning the actual ice cream making. I also answer any questions the students have about liquid
nitrogen, usually these are questions like “what happens if you drink it” or “how can it burn you if it’s
cold”. Next begin the ice cream making process.
Steps to make ice cream:
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Pour the milk, half and half, sugar, and vanilla into the mixing bowl.
Stir until the sugar is dissolved.
Put on the safety gloves and glasses.
Begin to pour in the liquid nitrogen.
a. Pour in a little bit of liquid nitrogen.
b. Wait a few seconds.
c. Stir the mixture.
5. Repeat step 4 until the ice cream has reached the consistency desired
6. Serve the ice cream
After step two, you can show the students the mixture and explain that right now it is a liquid. A brief
discussion can then be had about what will happen to the liquid when the liquid nitrogen comes into
contact with it.
If you want to add cookies or candy to the ice cream, you can add these to the mixture after step two. I
left my ice cream as plain vanilla and then let the students put chocolate sauce on theirs after if they
wanted.
Balloon Activity:
After making the ice cream, if there is any liquid nitrogen left, you can demonstrate what happens to a
balloon if you put it in liquid nitrogen.
First blow up a balloon and put it in your mixing bowl (after the bowl has been rinsed out). Next pour
liquid nitrogen over the balloon. As the liquid nitrogen hits the balloon, the balloon begins to seemingly
deflate; the liquid nitrogen is so cold that the oxygen particles in the balloon slow down and therefore
take up less space. You can think of this as the oxygen turning into a liquid. Once the balloon is
“deflated” you can take it out and hold it. The balloon will begin to “inflate” as the oxygen particles once
again speed up. After it is fully inflated the students can pass the balloon around to verify that it is back
to its original form.
Acknowledgements:
The recipe used here for the liquid nitrogen ice cream comes from the Steve Spangler web site. The
website also contains some additional facts about liquid nitrogen and a video of Steve Spangler
performing the experiment.