What you will need:
plastic zip lock bag
sharp pencils
500 ml water
 
This is a good experiment to do outside, over a sink or tub to catch the drips. Fill the plastic zipper-lock bag with water more than half full. Don’t use sandwich bags or you will get wet. Seal the bag and then take your pencils or skewers and carefully poke them through the bag and through the water, out to the other side.
Are you getting soaked? You shouldn’t be. There may be a few leaks and drips, but the bag should seal itself around the pencil and keep the water from spilling.
How does this work? The plastic bag is made of polymers. Polymers are long chains of molecules. When you poke through the plastic, you are stabbing between the long strands of polymers and the bag seals itself around the pencil keeping the water inside. Just watch out when you remove the pencils. Shower time!
 

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