Leak Proof Bag Science Experiment : Fizzics Education


Leak Proof Bag

Leak Proof Bag

Follow FizzicsEd 150 Science Experiments:

What you need

  • One Zip Lock bag
  • Water (enough to fill up the Zip Lock bag)
  • Five Sharp pencils


Leak proof bag experiment materials - 3 pencils, a cup of water and a zip lock bag
1 A zip lock bag filled with water

Fill the ziplock bag with water and close it.

2 A sharp pencil pushed through a zip lock bag filled with water

Hold up the ziplock bag and poke it with the sharp end of the pencil. Try fast vs. slow… which works better? Push the pencil all the way through the bag!

3 A red and an orange pencil pushed through a zip lock bag filled with water

See how many pencils you can stab into the bag before it starts to leak!

4 A student watching a purple liquid fizz

Why does this work?

The bag is made from a flexible plastic polymer!

When you stab the pencils through the bag, the plastic polymer moves apart creating the hole. Once the pencil has moved through the hole, the polymer pushes back up against the pencil to create a temporary seal with friction.

Variables to test

More on variables here

  • Does this make a difference with hot vs. cold water?
  • Try different brands of zip lock bags.
  • Can you use thin vs. thick pencils?
  • What about other objects like bamboo skewers, sewing needles or tomato stakes?

Learn more!


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