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There are lots of things you can do with gummy bears. Eat them…Eat some more of them…Umm, put them in your mouth and chew and swallow them…Okay, maybe there’s just the one thing. But it’s a pretty great thing!
Today we’re going to add a second thing to that first thing. Because today we’re going to use gummy bears in a little science experiment that will help us learn how water behaves. Get your gummies ready!
Materials:
- Water
- Small Bowl
- 2 Gummy Bears
- Paper towel
- A ruler
Process:
- Choose a gummy bear.
- Give it a name and a backstory. Is it Ricardo, the swashbuckling pirate gummy bear? Elizabeth, the firefighting gummy bear? You’re going to be with this bear for a while so you might as well give it some personality.
- Plop Ricardo or Elizabeth or Steve or whoever into your bowl, and then fill the bowl partway up with water. Measure how deep the water is with your ruler, being very precise, and either memorize it or write it down somewhere.
- Not much is happening yet, so now is a perfect time to make some observations. What does your bear look like? Were there any immediate changes to the bear or the water?
- Make a prediction: what do you think will happen to your bear if you let it sit in the water for a few days? Why do you think that?
- Now, let your bear sit in the water for a few days. Check on it at least once a day. Observe what changes, if anything.
- On day 3 or 4, go ahead and pull your bear out and set it on a paper towel. Grab a second gummy bear and compare. What is different about your water bear when you compare it to a bear that has stayed dry (by the way, we call that bear a “control”)?
- Measure the water left in the bowl. Is it different from the amount that you had initially? If so, where do you think that water went?
- Answer some of these questions:
Do your gummy bears have bubbles on them?
Are they larger?
Did they change the color, or smell, of the water?
Do they float, and did they before?
Can you see through the gummy bear?
How do they feel? Do they bounce?
Summary:
You’re probably thinking that the gummy bear grew because the water soaked into it, which also explains why the water level was slightly lower after the gummy bear came out. Well, you would be right.
Well, partially right. You probably spilled a small amount of water when you removed the bear, and some of it almost certainly evaporated since it was left out in the open air, but…Yeah, some of it went into your bear, and it blew your bear up like a tiny little sugary water balloon.
That sugar is key to what’s happening, actually. See, when gummy bears are made, they’re originally liquid: sugar, flavor, color, and gelatin dissolved into water. When water has things dissolved into it, we call that a solution. This warm gummy bear solution is poured into gummy bear molds and left to cool and dry out, but not quite all the way dry. As the gelatin cools it starts to set up, and it forms almost little containers that hold onto water inside of them. Think of gelatin as teeny tiny bubble wrap with water inside the bubbles. That water is still a solution of sugar and flavor and color dissolved together, and there’s just enough of it in the gummy bear to make it gummy and delicious.
If you’ve ever had a gummy bear that’s been left out in the open air for a while, you know what it’s like when that water eventually escapes the gelatin. Hard and a little bit gross. And maybe dusty, depending on how long it’s been left out. You really should clean your couch cushions more.
Anyway, back to your bear. You put it in the water and water flowed inside and swelled it up. Now, think about that warm liquid gummy bear solution. It was sugar and color and flavor and gelatin and…water. Lots of water. As the solution became bears, everything stayed but most of the water…And that means that the water solution that’s inside a gummy bear has way more of all that stuff mixed in with it than when there was lots more water. We call that a strong solution. In this case, a very strong solution.
Well, nature likes balance, and things naturally move around the universe to achieve that balance. You’ve noticed this if you’ve ever left a window open when it’s cold outside and warm in your house. There’s more heat inside than outside, and so heat moves out through the window until your house is as cold as the outside. Then things are in balance. We call this diffusion, and you can see it in action by just dripping a single drop of food coloring into a clear cup of water and letting it do its thing. Eventually, it will be spread out perfectly evenly. Diffusion in action.
What happened to your bear is a very special case of diffusion called osmosis. See, diffusion is when anything moves to achieve balance, or equilibrium. Osmosis is when water moves to achieve balance, and it moves through something called as semi-permeable membrane, basically a wall that allows some things through but not others.
Your bear is made of a semi-permeable membrane: gelatin. It allows water in but is much worse about letting sugar, color, and flavor out. Now, since the water inside is a very strong solution, and the water on the outside isn’t a solution at all, the system is out of balance, and water will slowly move through the gelatin into those gelatin “bubbles” and swell up the gummy bear in its quest to achieve balance between both parts of the system.
It probably didn’t work completely; you can taste-test your swollen bear to see that it still tastes a bit sweet, but the extra water has made the flavor kinda weak. You can taste the water, too, because it’s likely that some sugar and flavor escape out of the bear…But not very much. That’s osmosis in action.
Now that you've gotten a taste for science, join us over at Corteva Agriscience ScienceWorks! Boulder while learning about the animals that make the Hillside their home, discover how we manage and engineer our water systems, track moving weather systems, and see us feed the animals in our Pond!
