Potato cells contain water along with dissolved minerals and salts that help it stay firm and healthy. When a potato is placed in different surrounding solutions, water moves in or out of its cells depending on how concentrated those solutions are. This movement of water reveals important information about the internal environment of the potato.

In this activity, you will estimate the approximate concentration of the solution inside a potato using the process of osmosis. By placing potato strips in solutions of different concentrations and measuring how their mass changes, we can determine the point at which there is no net movement of water. That concentration will be closest to the natural salt and mineral concentration within the potato cells.

Why are living things, whether they are gigantic whales or tiny insects, all made up of cells that are incredibly small? Cells are always small; a whale doesn't have bigger cells than an ant – it just has a lot more of them.

For a cell to survive, it must constantly absorb essential nutrients and move them inside and simultaneously get rid of waste. But as cells grow bigger, it becomes harder for materials to move in and out efficiently.

In this activity, you will build model “cells” out of corn starch to explore how the size of a cell affects how quickly substances can diffuse inside it.