Pencils in a Plastic Water Bag

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What do you think would happen if you poked a plastic bag filled with water using sharp pencils? Let us carry out this amusing experiment to find out the answer. All you will need is a Ziplock plastic bag, water, and some colored pencils.

Steps:

  1. Fill about 2/3 of the Ziplock plastic bag with water.
  2. Seal the bag.
  3. Poke the bag with a sharp pencil, but do not take it out.
  4. Repeat step three as many times as you would like.
  5. Now you have a Ziplock plastic bag filled with water and decorated with an array of colorful pencils; why does not the water leak out?

The Science Behind the Activity

Plastic is composed of flexible polymer molecules. When you push a sharp pencil into the bag, the molecules forming the bag shift to allow the pencil to penetrate. Then, they immediately mold again around the opening surrounding the pencil, forming a seal preventing the water from leakage.

Reference

acs.org


Cover image source: niftythriftydiyer.com

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SCIplanet is a bilingual edutainment science magazine published by the Bibliotheca Alexandrina Planetarium Science Center and developed by the Cultural Outreach Publications Unit ...
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