---
title: Leak-Proof Bag Experiment | Science Activities | Extended Notes
description: Demonstrate how polymer chains work together to prevent water from leaking out of a plastic bag with this after-school chemistry experiment for kids.
---

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# [Leak-Proof Bag Experiment | Science Activities | Extended Notes](https://www.extendednotes.com/blog/after-school-activities/leak-proof-bag)

 Written by [Admin](https://www.extendednotes.com/blog/author/admin) | Feb 2, 2017 5:00:00 AM

Demonstrate how polymer chains work together to prevent water from leaking out of a plastic bag. Plastic bags are made out of polymers, which are long chains of individual molecules, called monomers. When the plastic bag is punctured with a sharpened pencil, the polymer chains are separated without being broken.

 

#### **Materials:**

 

- Sharpened pencils
- Zipper-lock plastic bags
- Water
- Paper towels

#### **Instructions:**

 

- Make sure the pencils are sharpened to a point.
- Fill a zipper-lock bag between ½ and ¾-full with water.
- Gather hypotheses. What would happen if you pushed a sharpened pencil through the water-filled bag?
- Holding the bag in one hand, use the other hand to slowly, but firmly, push one of the sharpened pencils through one side of the bag. Make observations.
- Repeat with the other sharpened pencils.
- Once finished, hold the bag over a sink to remove the pencils.

Source: [http://www.stevespanglerscience.com/lab/experiments/leak-proof-bag/](http://www.stevespanglerscience.com/lab/experiments/leak-proof-bag/)

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