Gillian Gehring from The University of Sheffield came in to school to teach us about temperature. She did lots of demonstrations of how cooling gas to less than -200 degrees turned it into a liquid. It was amazing!
She cooled some daffodil heads which we then crushed. They were very brittle.
Gillian cooled the gas in a ballon downing the liquid nitrogen. The ballon was deflated as the air turned into a liquid which gathered at the bottom. As it warmed up again, the balloon was again inflated.
Gillian used the pressure of the nitrogen turning into a gas to inflate a balloon.
Finally, Gillian had a bucket of soapy water which she poured the remains of the nitrogen on. Just look what happened!