Author: Lucy W.
After going to bed at 07:00 UTC (03:00 EDT) to submit three hastily written limericks for the Question of The Day in on time (and staring confusedly at the next astro psets), I awoke at 11:00 EDT, worrying over how the blog post I had to submit would turn out.
Instead of a two-hour social block like last Saturday, we had a special guest speaker, Dr. Larry Sverdrup, come and present a bunch of epic science demonstrations, starting off with a bang! No, really, an actual bang.
Normal and Active 15000 V Jacob’s Ladder 
Electrons come into contact with added nitrocellulose at the top of the Jacob’s Ladder, creating an explosion
The Zoom was packed with 189 people. If that didn’t wake them up, I don’t know what would.
From here, Dr. Sverdrup talked a bit about electricity—specifically, conductors of electricity. Through his chosen inductees, we were able to experience conducting an electric current by holding hands and the difficulty of prying your hands off something that is conducting an electric current at a high enough voltage. We also found out that purified water doesn’t complete a circuit, but tap water does (this is because impurities in the water conduct electricity).
The next exciting display was a showcase of infrared radiation. Infrared radiation is a type of electromagnetic radiation, or light, that can be used to see thermal radiation. The inductees and Dr. Sverdrup then demonstrated this by showing both a regular visible light camera and infrared light camera (in black and white).
Dr. Sverdrup demonstrates how an opaque orange balloon as we perceive in visible light is see-through with infrared light, as it is not giving off much thermal radiation 
Dr. Sverdrup shows how a scratched-up aluminum sheet that is not very reflective when seen in visible light acts as a smooth mirror in infrared light
Moving on with his awesome presentation, Dr. Sverdrup did a number of science-y presentations involving liquid nitrogen. First, he demonstrated the Leidenfrost effect, and participants watched in amazement as the insulated vapor layer kept the liquid nitrogen from boiling off rapidly in Dr. Sverdrup’s room. He then poured some liquid nitrogen into a bowl of water, and the liquid immediately turned into vapor as it hit the water. Whereas when he poured some liquid nitrogen on his hand, it ran off immediately like a liquid and didn’t linger. He explained that if he were wearing a glove, the glove would soak in the liquid nitrogen and immediately harden, and joked that in some cases in the lab, it might be better to not wear safety gloves. To show this hardening effect, Dr. Sverdrup to a piece of pliable, black rubber and dipped it into the liquid nitrogen. He took it out, and the dipped portion was covered in a frozen white film. When the rubber was smacked onto a nearby table, the frozen portion shattered into small, sharp shards, like glass.
Dr. Sverdrup also filled a colorless, clear balloon with some liquid nitrogen and left it in the back of the room to expand (the liquid nitrogen turns into vapor as it heats up to room temperature) for the rest of the presentation. Many participants grew worried as the balloon kept expanding, fearing that it might burst at any given moment.
A short metal tube that Dr. Sverdrup dropped a round magnet down to show the effects of Lenz’s law (Lenz’s law states that the direction of the current induced in a conductor by a changing magnetic field is such that the magnetic field created by the induced current opposed the initial changing magnetic field) was also laid in the liquid nitrogen. Although the magnet moved slowly through the tube at room temperature, the magnet moved significantly slower through the tube after it had been frozen.
Then, perhaps feeling a bit hungry, Dr. Sverdrup decided to have some fun and dipped a banana and a graham cracker into the liquid nitrogen, and showed how it too, hardened after being taken out. Dr. Sverdrup demonstrated how hard the banana was by hitting it with a hammer. This excited the #banana-eating channel on the SSP Discord. Dr. Sverdrup did not eat the banana, as he said eating it in the past has led to tooth cracks, and instead he ate the briefly dipped graham cracker and breathed some nitrogen vapor out through his nose, like a mythical dragon!
Nearing the end of the presentation time limit, Dr. Sverdrup quickly heated up a metal tube on one end and turned the apparatus vertically. The tube immediately gave off a high, loud, and rounded note, not unlike a note on the theremin, and maintained the same pitch until the very last minute of our time with Dr. Sverdrup, ending the showcase on a literal high note.
This presentation was truly the highlight of the day, and it’s even more impressive that this is Dr. Sverdrup’s 50th presentation of it at SSP.
And thus, the pages close on the second chapter of SSP. Week three is now starting, and I can’t wait to see what it has in store.
P.S. To the readers in the United States: have a wonderful Fourth of July! And as the colorful fireworks light up the sky, remember to stay safe.
Hello! My name is Lucy, and I am a rising senior from Oxford, Ohio. I enjoy playing video games, making stop-motion LEGO animations, and spending my time learning about astrophysics and quantum mechanics theories on YouTube (it’s not procrastination if it’s educational). I like to think of myself as funny, but that is easily debunked by my sad attempt at stand-up comedy during my freshman year talent show.
