This past February, Lafayette celebrated National Engineers Week with a wide variety of activities. On the final day of the week, a representative from Air Products came to display some of the wonders of liquid nitrogen. I knew little about liquid nitrogen before the demonstration, besides the infamous fact of its extremely low temperature. The woman from Air Products, Winsome Condra, showed just how cold, and dangerous, the liquid is; but every demonstration amazed me. Condra used it to freeze a banana, which then became so rigid that she was able to use it to hammer a nail into a wooden plank. She dipped a flower into the liquid and the pedals crumbled at the touch. But my favorite part of the event included the balloons that each member of the audience inflated. Condra took over twenty balloons and fit them all into a small cylinder-shaped container of liquid nitrogen. As she pushed each balloon in, it seemed to deflate in upon itself. Then she used tongs to take out every crumpled bit of rubber and drop them on the floor. To the audience’s amazement, the balloons began to re-inflate themselves, one by one, stretching back to their original form. Once Condra explained the reasoning of this seemingly mysterious action, it all made sense. The idea actually related to what I had learned last semester in my chemistry course about the relation of volume and temperature of gases. Charles’ Law shows that as the temperature of a gas decreases, the volume also decreases. The temperature of liquid nitrogen is much less than that of the air in the balloon so when the gas in the balloon came into contact with the liquid nitrogen, its volume decreased. But when it was removed from the liquid and returned to room temperature, it reverted back to its original volume.
The crowed seemed to enjoy each experiment just as much as I did, and their intentness was well rewarded. At the end of the demonstration, Condra used liquid nitrogen to make ice cream for everyone! Unfortunately I gave up dessert foods for Lent so I was unable to taste the ice cream, but it got good reviews from my peers. I loved the entire demonstration, and I was surprised that the seemingly simple ideas I had learned in chemistry were being applied at the industrial level. This gave me the realization that what I’m learning now is not just for school, but it really is useful and something I cold possibly use in my future employment. Even the seemingly minor or trivial ideas taught in a classroom could have great importance in the workplace.