A few weeks ago my sons and I found these super fun paintballs. They’re small gel balls filled with washable watercolor paint, and perfect for kids to explore all sorts of cool science ideas. The first time we experimented with them, we discovered that the harder the paintballs were thrown, the bigger the splat they made on a piece of paper. We also noticed that the paint dripped down the paper after the paintball exploded. My son asked me why, and I decided to explain it to him with a quick STEAM activity.
Painting Pumpkins with Paintballs: A Quick STEAM Activity
In our first STEAM activity with the paintballs, we used watercolor paper to maximize the absorbency of the water color into the paper. But even with the watercolor paper, the exploded paintball paint dripped all the way down our paper.
We brainstormed some ideas of other materials we could use, and decided to try some left over coffee bags I had from making curtains.
Coffee bag Paintball STEAM Activity
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- 1 burlap bag
- 1 bag of orange Goblies paintballs
- orange and brown acrylic paint
- paint brush
- 2 nails
Step 1: Cut a rectangle (approximately 10 inches by 12 inches) out of one of my coffee bags.
Step 2: Nail the cut out coffee bag piece to the fence.
Step 3: Throw orange Goblies paintballs at the coffee bag material.
We took the coffee bag material down, and compared it to our paintballs on the watercolor paper. Immediately we noticed a difference! The paint from our paintballs on the coffee bag did not drip. Instead, the paintballs had left round(ish) circles of orange paint.
My son and I discussed why the paint didn’t drip on the coffee bag material.
My son: “The paint didn’t because all the paint went into the coffee bag”.
Me: “Exactly! The coffee bag material absorbed all the paint from the paintball.”
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The Science Behind our Paintball Pumpkin STEAM Activity
Material that is absorbent is hydrophilic, meaning “water loving”. If a material is hydrophilic, then the material’s molecules bond (or connect) with water molecules. Both the paper and the coffee bag material contain the molecule cellulose, which bonds with water. The coffee bag material has a greater amount of cellulose molecules than the water color paper. So when watercolor hits the coffee bag, more of the watercolor paint is absorbed. When the watercolor hits the paper, on the other hand, there are fewer cellulose molecules for the water to bond with, so the paint drips down the paper.
Seeing our masterpiece gave me an idea. Since we now had perfect little balls of orange paint, I thought it would make a perfect fall decoration. So I added a little brown stem and painted an orange circle around each paint splat. Now we had a perfect little fall pumpkin decoration from our pumpkin STEAM activity.
Looking for other fun STEAM activities? Try one of these!
Caramel Apple Rock Painting Fall STEM Activity
Halloween Rock Painting for Kids using Physics!
Or try any of my other Science inspired ideas!
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