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Pencil Poke Magic


What You Need:

  • 1 ziplock bag

  • Water

  • 5 to 10 sharp round pencils

  • A sink/ big bowl


Safety:

Adult supervision recommended. Push pencils slowly and keep fingers away from the pencil tips.


Step by Step Instructions:


  1. Fill the ziplock bag about half full with water and seal it tightly.

  2. Hold the bag over the sink with one hand supporting the top of the bag.

  3. With your other hand, take a sharp pencil, push it straight through one side of the bag and out the other side.

  4. Pause..no leak!

  5. Repeat with more pencils, spacing them out.

  6. Gently tilt the bag - still no dripping or leakage!

  7. When finished, pull pencils out over the sink to let the water drain.

  8. Wash hands and high-5 your scientist!

Fun Fact:

Why Doesn't the Water Leak Out?


The plastic ziplock bag is made of long stretchy plastic chains (polymers) that hug the pencil and make a seal. Water's water tension helps tiny gaps stay closed, so water droplets don't escape.


Imagine the water molecules are best friends holding hands really tightly. They don't want to let go, even when the pencil pushes through. The plastic and the "hand-holding" water molecules team up to close the hold and stop the leaks.
Imagine the water molecules are best friends holding hands really tightly. They don't want to let go, even when the pencil pushes through. The plastic and the "hand-holding" water molecules team up to close the hold and stop the leaks.


 
 
 

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