Zoey & Sassafras: Caterflies and Ice {Book Science Activity}
There are many reasons I love the Zoey & Sassafras series by Asia Citro. They are the first chapter books my 5-year-old actually enjoys, and they are all science-based!
Reading them always sparks great questions and learning opportunities.
In Zoey and Sassafras: Caterflies and Ice, Zoey uses salt to melt ice and save the caterfly eggs, but it leads to an unexpected problem—the catnip plants wilt!
Why does this happen? The answer lies in osmosis, a fascinating science concept. Let’s explore osmosis with a fun potato experiment taken directly from the book!
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After reading the book my kids wanted to try the potato experiment from the book. Zoey’s mom uses it to show Zoey why the plants wilted. She explains that it’s because “Things like to be equal when they can” (pg. 58).
The process she’s actually explaining is Osmosis.
We had a great time completing the experiment and I created a worksheet for us to capture our results just like a real scientist! (Plus we’re homeschoolers and it made a great work sample).
My kids are 5 and 7, kindergarten and 2nd grade, but this simple experiment could be great for any elementary school age kids.
What is Osmosis?
Osmosis might sound like a complicated word, but it’s simply the movement of water from one place to another through a semi-permeable membrane (like the cell walls of a potato).
The water moves to balance out concentrations of substances like salt or sugar. In nature, osmosis helps plants absorb water and keeps our cells working properly.
This potato experiment lets us see osmosis in action with just a few items you probably have at home.
Supplies
- 2 bowls of equal size
- measuring cup
- measuring spoon
- water
- salt
- potato
How to do your own Potato Experiment
Before getting started ask your kids what Zoey’s mom always tells her the rule is for experiments.
There’s a good chance they won’t remember so try prompting them by asking “How many things do you change?”.
The rule is one thing, you change only one thing so you know with great certainty that it is causing the effect you observe. This can also be a great time to talk about cause and effect.
1 – Prepare Your Potato:
Start by slicing your potato into thick pieces. You will need at least one for each bowl. You want them to be the same size and thickness as much as possible (remember Zoey’s mom’s rule for experiments).
I removed the skin so that all pieces of the potato where the same.
2 – Set Up the Bowls:
Be sure to label your bowls in case things get moved around during your experiment. We just used numbers written on masking tape.
- In one bowl, pour water until it’s about halfway full. We used 2 cups of water. You can use a different amount so long as it’s the same in each bowl. (Record the amount on your worksheet.)
- In the second bowl, do the same but mix in salt until it dissolves. We used 2 tbsp of salt. You can use more, the amount is up to you. (Record the amount on your worksheet.)
3 – Add the Potato:
Place one potato slice in each bowl and let them sit for at least 30 minutes. You might notice changes sooner, but the longer you wait, the better your results!
4 – Observe the Magic:
After the time is up, take the potato slices out and compare. We used a large spoon to pull them out. Observe what they look like and make sure to feel them, too!
The potato in the plain water should feel firm and plump, while the one in saltwater will likely feel softer, maybe a bit rubbery and bendy.
We checked ours after 30 minutes and then again overnight.
5 – Record your Data
Zoey always records her experiments and observations in her science journal. We just have a one page worksheet.
Kids can record what the slices looked like before they went into the bowls, what ingredients went into each bowl, and what the potatoes looked like after 30 minutes and a longer period of time (how long is up to you.)
Review what happened
Last you can write or discuss why this happened. You can read the explanation from the book (pg. 58/59) or explain osmosis. If you review osmosis before the experiment you’ll probably need to discuss it again afterwards.
You can also watch this fun video that uses the same experiment.
