The program that I put together for the children was arranged in two parts.  The first part I hoped would be educational, and focused on temperature and matter; the last part was a bit of "chemistry magic" and was just for fun.

I began by discussing with the children the notion of temperature.The photos show the children using a thermometer to measure the temperatures of hot water, room-temperature water, ice, and a cold ice-salt water solution.  One student measures the temperature of the last solution, which was -10 ºC.  What I wanted to get the children to appreciate was that you can have a temperature less than zero degrees.

I then discussed that there are three states of matter, solid, liquid, and gas, and that changing temperature was one way to change the state of matter.  After reminding the children of the steam, water, and ice that they just examined, I showed them a number of more dramatic examples.

We demonstrated that at -195 ºC, a very, very cold temperature, nitrogen, a component of air, becomes a liquid.  We showed as well that at such a low temperature that certain gases, like carbon dioxide, can be transformed into solids.

The children and I learned together that at this very low temperature of -195 ºC, the properties of solids changed.  We found that a banana at this temperature becomes so hard that it can be used to hammer a nail through a block of wood.  A student and I are dipping a long-stem rose in liquid nitrogen; when this rose is cooled to -195 ºC, it shatters like glass when dropped on the floor.

One photo shows the children that when a stream of cold dry air meets warm humid air, fog is made.  They thought this was really cool!

The last half of the show was more entertainment-focused (exploding balloons, imploding coke cans, solutions that changed color, etc) and silly.  Another student helped me pass electric current through a pickle.  What is amazing about this experiment is that the pickle lights up like a light bulb, emitting yellow light.

May 2004