- plastic baggie
- sharp pencil
- Fill a baggie about 3/4 of the way full with water and seal it shut.
- Make sure your pencil is sharpened. (The sharper the better!)
- Hold up the baggie with one hand and use the other hand to firmly push the pointy end of the pencil through the side of the bag. Continue pushing it until the point is also coming out the other side of the bag.
- Observe what happens!
Question to Spark More Curiosity & Critical Thinking:
Is this what you expected to happen? Why or why not? What do you think will happen when the pencil is pulled out of the baggie?
What’s Going On:
No water spills out the holes because ziploc bags are made of a polymer. Polymers have long chains of molecules that are flexible. When you poke a sharp pencil through the baggie, the pencil slides in between the chain of molecules that make up the polymer. The molecule chains make a seal around the pencil that won’t let the water out.
Want to go even further?
Even more activities to inspire creativity and critical thinking for various ages:
- Can you put more than one pencil through your baggie at a time?
- Try this experiment with other materials.