Let’s talk about the word osmosis. What does it mean? Osmosis is a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane. In this process, water molecules move towards a more concentrated substance. This activity doesn’t just show the osmosis procedure, but it also allows for kids to make predictions and form a hypothesis of what will happen.

So before we get started, let’s get a pen and a piece of paper and predict what you think is going to happen to the gummy bear while it’s in water. 

Supplies Needed

  • Mason jar or glass cup

  • Gummy bears

  • Water

  • Pen

  • Paper

  • Ruler

  • Spoon

  • Stop watch


  • Select two gummy bears as your control. Using your ruler, measure the size of the gummy bears. Set your control gummy bears on a plate and leave them there.

    Your control in the science experiment is your sample of materials you don’t experiment on. They stay in their original state the entire time. You can then compare your experiment results with your control to see how/what they have changed.

  • Place two gummy bears in the jar of water.

  • Set your stop watch for time intervals of 5, 10, 20, 40, and 60 minutes, 2 hours, and then at 4 hours.

  • Carefully remove the gummy bears from the water at each time period and measure the gummy bears with the ruler. Note on your paper their size and what other changes you observe at each point. What is happening to it’s color?

  • Then carefully place them back in the jar until the next time interval is up.

  • At the end of your test period, place the wet gummy bears next to your control gummy bears. What do you notice? How has you test gummy bears changed? Have your control gummy bears changed?

Science Behind the Experiment

  • The gummy bears grow because of osmosis. There are more water molecules in the jar of water than there are in the gummy bear.

  • Osmosis causes some of the water molecules to move into the gummy bear. As the gummy bear fills with water molecules, it gets bigger.

  • The gelatin in the gummy bear acts as a sponge, so rather than dissolving in the water, it absorbs it and grows.