Learn about semipermeable membranes. If you put eggs and sand through a colander, would they both fall through? Probably not. Only the sand would actually pass through the holes of the colander because the eggs are too large. The colander acts as a semipermeable membrane, allowing some materials through but not others. Let's explore some other semipermeable membranes -like what surrounds our cells to help keep our bodies working and healthy. And eggs are like giant cells. They are a perfect thing to use to explore the science of semipermeable membranes, osmosis, and diffusion. We'll even experience a cool chemical reaction when we place an egg in vinegar. What do you think will happen when this chemical reaction is complete?