Poke It!
Amaze your friends, family and schoolmates by poking pencils through a
ziplock bag filled with water. Imagine the shock when nothing leaks out.
Materials
- Sharpened pencils
- Plastic zip-lock bags
- Water
- Some paper towels just in case!
Watch Video
Process:
Before you try this over your friends head, we highly recommend you
give it a whirl outside or over the bath tub!
1) Get out your sharpened pencils.
2) Fill a zip-lock bag up with water and seal it.
3) Ask the audience for a brave volunteer.
4) Raise the water filled zip-lock bag over the volunteers head and ask the
audience what will happen when you poke holes all the way through it will
your pencils. You know what they are going to say. But you know the secret!
5) With the bag over head, poke your pencils all the way through the bag.
6) Watch the crowd roar as no water leaks from the holes made and thank
your brave volunteer!
The Science:
Zip Lock bags are made from plastic. Plastic is made of polymers which
are long chains of molecules cross linked together. Polymers are what
makes plastic bags and balloons stretchy. When we poke through the zip
lock bag with pencils the polymers are pushed aside but remain bonded
by the cross-links - keeping the water inside. The polymers re-seal around
the pencil. Amazing!
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