Diffusion Lab Class #5

Diffusion is the net movement of molecules down their concentration gradient, and it occurs in solids, liquids, and gases. Even though the movement is down the concentration gradient, the molecules can move in any direction as long as the membrane is permeable to the molecule.

On the 4th of September, we explored this topic by performing two labs. In the first lab, we first created "cells" from dialysis tubing containing 15% glucose and 5% starch (8ml). Then we tested them with glucose strips. Then we added 1ml of iodine to test for starch presence. The higher concentration iodine moved into the lower concentration solution in the "cell". Then after 15 minutes, put the cells un a cup with 1ml of Benedict's on a hot plate. This tests for glucose presence.

For the second lab, we had three pieces of differently cut NaOH. First we measured the surface area of the cubes. Then we placed them in beakers full of water and then added a solution. After a couple minutes, we took the cubes out and re-measured the surface area. We observed that the cubes changed from a white color to a pinkish color. Diffusion took place because the molecules moved from the higher concentration solution to the lower concentration NaOH. However, the cubes were not fully pink in the center because we took them out too early enough for diffusion to happen thoroughly.