Entropic Forces in Single-Biomolecule Mechanics
Philip Nelson, University of Pennsylvania, DMR-25780
Broader impact, education, manpower
This year, Nelson added a middle-school component to the research
supported by the grant, doing hands-on science instruction for
seventh- and eighth-grade students at The Philadelphia School. Far
too much school science instruction is based on learning and
repeating poorly understood facts. We prefer to show students some
intrinsically bizarre phenomenon, let them play with it, saying as little
theory as possible, and ask for their ideas. Then we did some
quantitative analysis. Finally, we connected to other ideas—for example, the
prospects for hydrogen-powered cars.
We broke into groups of 3 and performed electrolysis of water. First
we got the emotional payoff of exploding the hydrogen! Then we
showed that chemically different gases evolved at the anode and
cathode, in 2:1 ratio, and also made a master graph across all
groups of the volume of gas evolved versus the total electric charge
passed through the system, obtaining a surprisingly accurate value
for the charge on the electron.