Of Jet Propulsion and third Graders

"We're gonna have a few visitors this Wednesday", my Professor told me. It was not too unusual to have visitors tour the lab with all the folk applying for the professor position now that Prof. Schaubert is going to leave us. The usual show and tell ritual with the Downconverters we made, I thought. It was a refreshing exclamation to learn that the visitors were grade school children from the Shrewsbury public school, third to fifth grade. Would I arrange for a few experiments to pick their brain, my Prof asked.

My Professor somehow got into this University outreach thing; his collaboration with the Climatic study folks did that I reckon. Part of that was hosting school children to show them what we do in out lab. Razi and I (often partners in crime) were to set up some popular science stuff to amuse the kids, but my Prof had to pick their brains with the happenings at the Microwave Remote Sensing Lab! Insane, I thought and decided to keep to my part of the job and not bother about the rest.

A few liters of liquid Nitrogen was arranged for and Razi and I would make ice-cream using it; including of course throwing in things making them go brittle and smashing them with a mallet. We did a test run the previous day with leaves, flowers, and rubber pipes and it was a smashing success! But would that teach the kids some Physics? Not much we thought. So we decided to do the ping-pong experiment to teach kids some Jet Propulsion!

Here is how the ping-pong experiment works. Take a ping-pong ball and poke an almost tangential hole in it with a pin. Hold in inside liquid nitrogen for a few minutes and throw it out on a flat surface. Now the Nitrogen inside the ball is going to experience a sudden temperature change and expand rapidly into a gas while shooting out of the hole making the ball spin like crazy. It was an absolute delight to see the ball spinning madly flushing out condensed moisture as the Nitrogen shot out.

So the next day after my Professor had bored the kids with his satellite images of Shrewsbury, Razi and I walked in like cool kids with all the liquid nitrogen. They loved the ice-cream we made by throwing in milk, vanilla, sugar and liquid nitrogen. The ping-pong experiment was a success! What more, one of the kids even explained (in his own non-technical language) how the experiment works- something which took me by shock. "Sharp kids", I exclaimed to Razi. Amidst all the fun with the kids, I learnt one thing: getting the attention of a bunch of grade school kids- not easy. Boy do I admire my grade school teachers now!