Liquid Nitrogen:
Liquid Nitrogen Basics
Description:
A fun introduction splashing Liquid Nitrogen.
Science:
We explain
- What is liquid nitrogen?
- How cold is liquid nitrogen? (-196 ? C)
- Why can we put our hand into it, and not freeze? (Laden Frost Effect)
- What is the cloud that you see? (water droplets, condensed by the cold)
- Is it dangerous to breath in the nitrogen gas? (No, the atmosphere is 78% nitrogen).
Special Requirements:
None
Safety Procedures:
Liquid Nitrogen Basics.pdf - 11kb
Apple Smash
Description:
An apple is frozen in liquid nitrogen, then smashed on a tarpaulin.
Science:
When the apple is initially put into the liquid nitrogen, the liquid boils furiously; we have just added a significant amount of heat. The apple takes time to cool (approximately 10min), since it has a high heat capacity. The extreme cold changes the properties of the apple, so that it becomes very brittle. When the pieces warm up again, they are very 'squishy', because the cells in the apple have burst when they froze (water expansion upon freezing).
Special Requirements:
None
Safety Procedures:
Liquid Nitrogen Apple Smash.pdf - 11kb
Hammering a Nail with a Banana:
Description:
A banana is frozen in liquid nitrogen, then used to hammer a nail into a block of wood.
Science:
When the banana is initially put into the liquid nitrogen, the liquid boils furiously; we have just added a significant amount of heat. The banana takes time to cool (approximately 10min), since it has a high heat capacity. The extreme cold changes the properties of the banana, so that it becomes very hard and brittle. Since it is so hard, we can use it to hammer a nail into a block of wood. If we smash the banana, we see that when the pieces warm up again, they are very 'squishy', because the cells burst when they froze (water expansion upon freezing).
Special Requirements:
None