This past week at Carter G. Woodson, the girls of Sisters4Science were visited by Rebecca Thompson! Becca is a PhD student studying Physical Chemistry at The University of Chicago. Becca has already worked for Project Exploration before with the S4S girls at Ariel, so when she came to Woodson she had an exciting new twist on an old experiment. The girls were going to work with liquid nitrogen!
Before we got down to things, Becca asked the girls if anyone knew what liquid nitrogen was. Sheneka said that she knew nitrogen was in the air we breathe! Not only that, but it’s found in our bodies too. While the nitrogen we find in the air and in our bodies is a gas, it can get so cold that it exists in a liquid form. This is what we used to do our experiments.
First, the girls got to see what happens when you put certain objects into a bowl of liquid nitrogen. Each girl was given a dandelion and asked to hold it in the liquid nitrogen for no more than 5 seconds. When they took the flowers out, they were all frozen solid! Dejah even tested how frozen her flower was by smashing it with a sledgehammer – don’t try this at home, folks! Next up, the girls predicted how liquid nitrogen could affect the air in a balloon. Kylie said that things normally shrink up when they’re cold, so the balloon should also get small. That’s exactly what happened! How did Kylie know that would happen? “Well,” Kylie said, “an ice cube takes up less space than a puddle of water!” Those are some great inference skills!