On November 1, 2020, volunteers from the Irvine branch of AYLUS hosted its tenth science exploratory class for the fall session. We used Zoom to host the lesson, and students, consisting of elementary and middle schoolers, had a great time participating.
Today was the fifth and final lesson of the biology unit in which we covered diffusion and tonicity. We started off with an experiment where we used a PhET simulation to demonstrate how molecules move from high concentration to low concentration. We moved on to an experiment where we filled half a container with a certain gas, and the other half with another gas then removed the barrier. We watched what happened to the concentrations of the gasses over time. We then explained how diffusion is the movement of molecules across a concentration gradient due to random motion. We then explained what a semipermeable membrane is and what happens to the molecules there. We then talked about how the cell membrane is selectively permeable, and only allows small nonpolar molecules to pass. We explained what homeostasis is and why it is so important. We then explained what hypertonic, hypotonic, and what isotonic solutions are and how animal and plant cells are affected by them. We ended off the lesson by explaining the difference between facilitated diffusion and active diffusion. Overall, the students seemed to understand how diffusion worked in biology and the diagrams/simulations we provided reinforced that understanding.
Screenshots:
Volunteers: Andy Chen (1.5 hrs), Aditya Verma (1.5 hrs), Brian Song (1 hr)