Gummy Bear Osmosis Experiment

OSMOSIS TERMS
Osmosis occurs when liquids flows through a semipermeable membrane allow some things to pass through them — most frequently liquids — but not others.

GUMMY BEAR COMPOSITION
Gummy bears are made from gelatin and water, starting as a liquid and cooling into a chewy, gummy solution. This is a result of the presence of gelatins, whose molecules are chain-like and create a solid matrix.

GUMMY BEAR EXPERIMENT: TAP WATER
Place the gummy bears in cups of water and set aside. Then discuss hypotheses — what do you think will happen to the gummy bears? The next day, the bears will have expanded, as water moved by diffusion through the bear’s semi-permeable membrane to reach an isotonic state where the concentration of water molecules inside and outside the bear were the same.

GUMMY BEAR EXPERIMENT: SALT WATER
Conduct the same experiment, this time soaking the gummy bears in salt water. Again ask students to predict the outcome: will the addition of salt change the outcome of the experiment in any way? If you soak the original, water-expanded gummy bears in salt water, they will shrink; osmosis will cause water to leave the gummy bear. However, if you soak new gummy bears in salt water, they will shrink immeasurably, as the bears’ gelatin construction will cause it to hold its shape and size, for the most part, even when water leaves the bear.