STEM Activity: Shape-Shifting Gummy Bears

Whether you’re a curious kid or a science-loving grown-up, have you ever wondered how water moves from soil into plants? You can look for answers by experimenting with STEM in the kitchen. And what could be better than getting to taste your latest discovery? We invite you to observe the power of osmosis with this sweet and salty shape-shifting experiment!

Materials Needed

• 3 small cups (glass or plastic)
• 3 gummy bears
• Plate
• Salt
• Spoon
• Sugar
• Water

Step-by-Step Instructions

1. Pour approximately ¼ cup of water into each of the three cups.
    
2. Add a spoonful of salt to one cup and a spoonful of sugar to another cup. Stir both cups until the salt and sugar dissolve.
    
3. Place one gummy bear in each cup.
    
4. Set the cups in a safe place to rest overnight.
    
5. The next day, use a spoon to remove the gummy bears from the cups. Place them on a plate.
    
6. Compare the gummy bears. Do you notice any changes? What do you observe about their size? About their texture?

What Are We Discovering?

Have you ever eaten a salty snack and felt thirsty afterward? One of the reasons for this is osmosis! If there is a higher concentration, or amount, of salt in the snack and a lower concentration of salt in your mouth, this imbalance causes the cells in your mouth to release some of their water, making it feel dry. Sweet snacks also can make you thirsty because there is a higher concentration of sugar in the snack compared to your mouth. Interesting, right? That’s why you feel relief after taking a drink because the salt or sugar from the snacks dissolves and your mouth is rehydrated.

Do you know how gummy bears are like the membranes in plants? Plant roots are a semipermeable (somewhat able to be passed through) membrane, meaning only water and certain minerals are able to pass through. Water wants to be at equal concentrations on both sides of a semipermeable membrane, like your cells, so it will flow in or out to restore balance.

When you remove the gummy bears from the cups, you’ll observe how different they look because they’ve either expanded from absorbing the water moving from a higher concentration of sugar water or shrunk from water moving away to achieve a new equilibrium in the salt water. Since the tallest parts of a plant have more sodium, water flows upward to dilute the sodium. This gravity-defying process keeps plants hydrated and delivers nutrients to where they’re needed most! Osmosis can be observed in other living matter too!

Find More STEM Inspiration

Did you have a blast exploring the exciting world of osmosis? STEM is all around you, just waiting to be uncovered. So, keep the bright questions coming and subscribe to our monthly emails to make more discoveries all year long!