10.31.2017
Experiment leaders: Brandon and Jake
This was our first week at KIPP during this school year—both we and the students were very excited to meet each other! Since it was Halloween, we gave all of the experiments a spooky twist. Students rotated through four experimental stations:
- Lava lamps. Students mixed vegetable oil and water in mason jars, then added food coloring to the mixture. Many were surprised that the vegetable oil rose to the top of the mixture and, furthermore, that the food coloring only colored the water. Finally, they added Alka-Seltzer tablets to the mixture and watched the mixture begin to bubble!
- Hydrogen peroxide decomposition. Students mixed hydrogen peroxide with a homogeneous phase catalyst (sodium iodide) in graduated cylinders. By placing a balloon over the top of the graduated cylinder, they observed oxygen gas evolving from the mixture. We varied the concentration of aqueous hydrogen peroxide solution and the variation in the rate of hydrogen peroxide decomposition (seen via the rate the balloons blew up) was apparent!
- Oobleck experiments. Students performed two experiments with oobleck, a mixture of corn starch and water which is a shear-thickening fluid. First, students mixed small amounts of corn starch and water in a 3:1 ratio (by volume) and made their own oobleck in Ziploc bags. Students were surprised that such a small amount of water could change the properties of the powdery corn starch. In another station, students experimented with the properties of a large container of oobleck. They sunk their fingers, hammers, and a weight into the mixture at various speeds and noticed the increase in resistance that came with increased applied force.