Liquid Nitrogen Freezing Marshmallows

Marshmallows frozen in liquid nitrogen become crisp and brittle. When eaten, the extreme cold condenses the water vapor in exhaled breath, creating a dramatic “dragon’s breath” fog effect.

1. Fill a large insulated bowl with liquid nitrogen.
2. Place regular-size marshmallows into the bowl.
3. Use a wooden spoon to push the marshmallows down and stir them so they freeze evenly.
4. Once frozen, remove a marshmallow with tongs and serve to a volunteer.
5. Instruct the volunteer to chew with their mouth slightly open and exhale gently.
6. Observe the “dragon’s breath” fog effect as condensed vapor exits their mouth and nose.

Liquid Nitrogen Marshmallows Experiment - Crus Center:

📄 Liquid Nitrogen Marshmallows - Harvard Natural Sciences Lecture Demonstrations: https://sciencedemonstrations.fas.harvard.edu/presentations/liquid-nitrogen-marshmallows

• Try different foods (cheese puffs, crackers) to see how they behave when frozen.
• Compare the texture of frozen versus room-temperature marshmallows.
• Use colored lighting to make the fog effect more dramatic during a demonstration.

• Safety glasses required for the demonstrator.
• Wear cryogenic gloves when handling liquid nitrogen.
• Use only wooden or plastic utensils (metal gets dangerously cold).
• Never serve marshmallows until liquid nitrogen has fully evaporated.
• Ensure volunteers understand to chew slowly — swallowing liquid nitrogen is extremely dangerous.
• Only serve in supervised, controlled demonstration settings.

• Why does frozen marshmallow create visible fog when exhaled?
• What role does water vapor in breath play in this effect?
• How does liquid nitrogen change the texture of marshmallows?
• Why is it safe to eat the marshmallows only after the nitrogen evaporates?
• How is this effect similar to seeing your breath on a cold morning?