Science Buddies: "Ask an Expert"

Hi, I would like to know if snap freezing can be done without liquid nitrogen or salted ice. I am trying to define the term because from what I researched, the procedure was to test purified water vs tap water alone without any additives. Please let me know if I need either of the two ingredients. Thank you

Hi,

I guess it depends on your definition of 'snap freezing'. There is one other way to snap freeze that I have used and that is with a dry ice-alcohol bath. Check stores and companies around your area to find out if any sell dry ice.

There may be a minimum amount that you have to buy so take a large enough cooler with you. Also, don't transport the dry ice inside your vehicle. Put the cooler in the trunk or in the back hatch area with the windows slightly open. Dry ice is frozen carbon dioxide and the CO2 is constantly vaporizing from the 'ice'. In an enclosed vehicle, the CO2 gas could build up to harmful levels over a period of time.

Here is a link I found to a method for making and using a dry ice-alcohol freezing bath: https://lifehacker.com/5972041/diy-cryo ... nstrations

Use a metal container for the dry ice bath to avoid breakage or cracking and insulate around it with Styrofoam peanuts or whatever you have.

Let me know if you have questions.

Sybee