Michael Kraft is from Plano, Texas and is currently pursuing a bachelor’s degree in chemistry at the University of Texas at Dallas. He is also the president of the Chemistry Student Association, a student chapter of the American Chemical Society.
After a significant amount of trial and error, the Chemistry Student Association at UT Dallas developed a simple, low-cost method of producing Dippin’ Dots at a large scale. After perfecting a successful process, our club decided to advertise and give out free Dippin’ Dots during our first meeting, and the attendance was high! Surprisingly high! Chemistry, free food, and school colors (orange and green for UTD) ended up being a winning combination.
So, we have taken everything we learned and provided it for you in the guide below. We hope your chapter will try making Dippin’ Dots using the procedures we’ve given you for your chapter meetings, or even for National Chemistry Week this year!
Dippin’ Dots Maker
- 2 clean and empty 2-L bottles
- Clean, deep Styrofoam cooler
When you handle liquid nitrogen, wear goggles, cold gloves, and closed-toed shoes and make sure all participants are wearing these items as well.
Dippin’ Dots are made by slowly dripping melted ice cream into a vat of liquid nitrogen. The design we have outlined can be modified to fit different needs. We chose to use two 2-L bottles to drip orange and lime ice cream, but the setup can be changed in a myriad of ways. As long as drops of fluid are dripping into the liquid nitrogen, the Dots will be formed!
To make this assembly:
- After cleaning out the bottles, use a thumbtack to make an evenly spaced matrix of holes on one side of the bottle. The patch should have 4 or 5 rows of holes and be 3 inches wide. The length will depend on how long the cooler is; you don’t want to drip ice cream all over the walls.
- Rotate the bottle 180 degrees and make another matrix of holes. The end product should be two patches of holes, on opposite sides of each bottle.
- Make a frame that will allow the bottles to rest securely over the mouth of the cooler. Make sure the bottles are level. The above picture shows a cardboard rectangle with two large notches for the neck to rest on, and a dowel for the other side to rest on. (When making the frame, note that duct tape will become very brittle and useless if it’s anywhere near the cold gasses released by the liquid nitrogen.)
- Using a ruler and marker, make a mark 3 inches up from the bottom of the inside of the cooler. This is the fill line for liquid nitrogen.
Preparing Dippin’ Dots
Materials: (makes about 2 L)
- Dippin’ Dots Maker, including the two cleaned bottles
- Enough liquid nitrogen to fill the cooler to the 3 inch mark
- Clean storage dewar
- Large funnel
- 1 L of melted ice cream
- 1 L of melted ice cream, another flavor
- Lots of napkins or paper towels
- Mixing spoon
- Serving utensils (bowls, spoons, etc)
- Safety glasses
Procedure: Note: This process takes a while. The vat will stay cool/ contain liquid nitrogen for at least 3 hours, so feel free to do this long before the event begins.
- Put on safety glasses.
- Using the dewar, fill the cooler to the fill line (3 inches deep).
- Wash your hands.
- Using the funnel, fill the bottles with melted ice cream. Cap bottles.
- Place the bottles over the mouth of the cooler, with one of the hole patches facing down. The ice cream will drip into the liquid nitrogen and freeze.
- From time to time, use the mixing spoon to agitate the liquid and break up any chunks that might form.
- After a while, the holes in the bottle will freeze over, and no more ice cream will drip out. Rotate the bottle so that the other, unfrozen holes are facing down. Use paper towels to wipe away the frozen patches and allow them to melt.
- Once all the ice cream has been dripped in, you can put aside the bottles and use the ladle to remove the Dippin’ Dots. IMPORTANT: After they are prepared, the Dots will be dangerously cold. If exhaling onto them produces visible “smoke,” they are too cold to eat and will burn your mouth. Never serve them when they’re too cold.
Shown: Way too cold to eat!
- The finished Dippin’ Dots can be stored in a regular freezer.
Dippin’ Dots can be the perfect treat for chemistry clubs to prepare and serve. Their preparation involves common and affordable materials, and the science behind how they’re made is a great conversation starter. They’re a lot of fun for everyone involved!
We’re always trying new things like this in our club: Check out https://www.facebook.com/csaatutd to learn more about what we do!
Oh, and since we’re on the topic, don’t forget to submit your outreach event into the NCW Event Locator, which allows others in the local section to find local outreach events via www.acs.org/ncw. Be sure to check the “National Chemistry Week” keyword and mention the time and place of the event in the event description, so those interested will know when and where to attend.
(Editor’s note: Mike sent us more pictures, and we enjoyed them so much we had to do a slideshow. We hope you like them, too!)
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