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What You Need:
- Ziploc Bag
- Water
- Several Sharpened Pencils
Fill the ziploc bag half full of water. Zip it closed. Hold a pencil in one hand while you use the other hand to poke the pencil all the way through the ziploc bag – have the pencil go in one side and come all the way out the other side. Repeat with more pencils. Does any water spill out? Do you know why? 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 the sharp pencil into the plastic the pencil point slides in between the chain of molecules that make up the polymer. The molecule chains ”hug” the pencil, making a seal around the pencil that won’t let the water out. What happens when you pull the pencils out?
Once you figure out how to do this one, try to get someone to stand still while you are holding the bag over their head. 
Poke the pencils through the bag to get them to trust your science…then pull the pencils out and see what happens! We tried it over the dog’s head. She liked it when the pencils got pulled out – a dog drinking fountain!
Here are some books websites that will help you demonstrate and understand polymers:
- Steve Spangler Science: Skewer Through a Balloon
- Cool Science Skewer Through a Balloon
- Science Squad Balloon Kebab
- Science Rocks! Slime Time (page 26)
- Naked Eggs and Flying Potatoes The Leakproof Bag (pages 128-131)
Words to Know:
Atoms - The smallest, most basic unit of matter. An atom is made up of a nucleus surrounded by electrons.
Molecules - At least two atoms held together by a chemical bond.
Polymers – Molecules arranged in a long chain.
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