The Leakproof Bag Pencil Trick – Science Project Ideas
As your family gears up for back-to-school season, use some of your newly bought goods to test out a cool effect! With just three simple materials you can find at home, you’ll be surprised with what they can do!
How we did it:
- Fill the plastic bag halfway with water.
- Use one hand and hold the plastic bag at the top for stability.
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Use a pencil to quickly pierce the bag and water!
What’s going on?
Most plastic bags are made of polyethylene, a polymer that is durable, flexible, and shaped like long strands. When the pencil is quickly pierced into the bag of water, the polyethylene molecules separate but don’t break, forming a seal around the pencil. If the pencil is pierced into the bag before the water is put in, the water will leak!
Try the experiment with a faceted pencil, a larger pencil, or a thicker plastic bag. What happens?