The final lesson plan to go with Travis’s Backyard BBQ Raddish Kids kit was quite scientific and a little over a five-year-old’s head. But thanks to two yummy experiments, even my kindergartner could keep up with the concepts involved.
First, I came to the table with a cup of clear hot water and a tea bag. I put the tea in the cup and asked Travis what he observed happening. “It’s turning golden,” he noticed.
I agreed, and more specifically told him he was seeing diffusion: molecules moving from an area of high concentration (close together) to low concentration (further apart). This actually wasn’t too foreign an idea for him, since he loves a book about Albert Einstein pondering molecules.
Explain to your child that osmosis is a specific case of diffusion, having to do with the movement of water molecules. Two suggested clips on diffusion and osmosis helped Travis understand a bit better, though to be honest, this part was over his head. To make it more accessible, you can give examples of each. Diffusion might mean:
the aroma you smell from a cake baking
food coloring dispersing in water
Osmosis might be:
wrinkled fingers in a bathtub
rehydrated dried fruit
Now it was time to experiment! For diffusion, I asked him what he thought would happen to a scent if we trapped it inside a balloon. Would we be able to smell it? His hypothesis was yes! We carefully added a few drops of vanilla extract to a balloon.
Inflate the balloon and tie the end into a knot. Place it in a closed box and let rest for 10 minutes or so.
When we lifted it out, the box smelled a bit like vanilla; in other words, the scent had diffused. The result was subtle, which I think underwhelmed Travis.
You may want to leave your balloon inside longer, or put more vanilla in it, to wow your kids with the results.
Next up: osmosis! For this one, we tested out the affect on gummy bears of being in plain water, salt water, and no water.
We filled out the provided chart with his guess for the results. After some prompting about those plump rehydrated raisins, he was able to surmise what might happen.
Big kids can really get scientific with this, filling in measurements before and after for color, length, width, thickness, and mass.
For the set up, you’ll need three clear jars. The first simply received a gummy bear. The second had the bear plus 1/2 cup plain water. The third had the gummy in a saturated salt solution; add 1 teaspoon salt at a time to 1/2 cup water until no more will dissolve.
We left them overnight, then checked in on the bears the next morning! Again, the results were a bit underwhelming, which may have been the vegan gummy bears we were using. But our plain water one looked a bit more plump, and our salt one looked a bit scrunched.
Well, if all else fails, you can watch this osmosis rap video!