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This is a two ingredient, two minute activity to try with your kids if they need a quick reset during the day. It breaks up screen time, and they might have some fun and learn too! I did this activity with just my older two kids (ages 10 and 8), because my toddler wasn’t really interested, and I think this activity is better for older kids (it probably would have gotten pretty messy with a toddler).
In this activity kids dip their finger into a cup of water that has a layer of cinnamon sitting on top, and their finger will stay dry! It works because cinnamon is hydrophobic, so I googled what other kitchen items are hydrophobic. Besides cinnamon, I learned cocoa powder, turmeric, paprika, and corn starch are all hydrophobic.
I decided we should test all the spices and powders to see which one works best, and to make the activity even more interesting and fun! Spoiler alert: it got crazy and messy, and only one of the kitchen items worked (I’m sure you can guess which one based on the title of this activity)!
Keep reading to learn all about our trials and errors, successes and failures, and then we want you to try it. Don’t forget to have fun, get messy, and be silly! It’s the best way to do science!
Watch the Activity:
We made a YouTube video and Instagram reel for the activity, so you can watch it on your favorite viewing platform. Each video is different, so you can watch both to see it differently each time. Check them out below.
Watch the video on my @EngineeringEmily YouTube channel:
Watch the video on my @engineering_emily Instagram page:
Activity Overview:
This is a two ingredient activity that’s great for older kids because there are opportunities to expand and experiment with additional ingredients. Not only is this an education STEM activity, it’s also a lot of fun! This activity is recommended for children ages 3+.
Materials:
- Clear cup or bowl
- Water
- Cinnamon
- Optional additional ingredients: cocoa powder, turmeric, paprika, and corn starch
Safety:
I recommend setting down a table cloth or place mat before beginning this activity. This will help protect your table from accidental cinnamon or water spills. Have extra towels on hand to clean up any water spills to prevent slips or falls. Do not place fingers in mouth, or especially eyes after placing them in the cinnamon/water. Wash hands immediately after doing this activity and before touching anything else.
Procedure:
- Fill a small clear cup or bowl about 2/3 full with water.
- Sprinkle a thick layer of cinnamon on top of the water. You want to use enough cinnamon that it completely covers the top of the water, so looking down into the cup you will only see cinnamon, and not water.
- Slowly lower your index finger into the cup of water, as deep as you can.
- Pull the finger out of the water and look at it closely: Is it wet or dry? (your finger should be dry, but covered in cinnamon)
- Optional: repeat steps 1-4 with different hydrophobic kitchen powders and spices such as cocoa powder, turmeric, paprika, and corn starch. Did you get the same or different results?
First we tested paprika. Once I sprinkled it on top of the water, it started to fall into the water (but most remained on the surface). When we placed a finger in the water it mixed the paprika into the water more and the finger came out wet and coated in paprika. You can see the pictures of our paprika experiment below:
Next, we tested corn starch. It came out of the container in a large clump. Then, like paprika, it mostly sat on top of the water, but it partially sunk down into the water. Once we pulled our fingers out of the cup, we realized we accidentally made Oobleck! This was a happy surprise and my kids had a blast playing with it! You can see the pictures of our corn starch experiment below:
STEAM Concepts Learned:
Cinnamon is hydrophobic, meaning it repels water. When we sprinkled it on top of the water it sat on top of the water instead of falling into the water or dissolving in it. When a substance is very hydrophobic like cinnamon, they will not mix with water at all. When we stuck our finger into the cup, it made contact with cinnamon before water. The cinnamon coated the finger, and this protected the finger from getting wet in the water.
What makes cinnamon hydrophobic? There are several compounds in cinnamon, including essential oils that give cinnamon it’s aroma that are non-polar (negative charge). Water is polar (positive charge) and the opposite polarities repel each other. Also, the chemical structure of the compounds in cinnamon, do not form hydrogen bonds with water molecules.
Cocoa powder, turmeric, paprika, and corn starch are all also hydrophobic, but didn’t work as well for this activity. That’s because they aren’t as hydrophobic as cinnamon. They are not soluble in water, but they also don’t repel it quite as much as cinnamon. Check out some of our previous experiments with turmeric, corn starch and cocoa showing their hydrophobic nature.
This was a fun summer activity for my kids. They especially had fun once we accidentally made Oobleck (be sure to check out my original Oobleck post for all the details on how to make it)! My kids were thrilled and it became a whole new activity with swamp monster messy fun.
Try it once and keep it clean using just cinnamon, or try it many times letting kids get messy as they test all the spices and powders in your kitchen like my kids did. Either way, I’m sure you and your kids will have a blast with this engaging activity. Let us know how it goes for you in the comments and what spices you try.
