A zip lock bag
Few sharp pencils
Fill ¾ of the zip lock bag with water. Seal the opening of the bag.
Hold the bag in one hand and carefully poke a sharp pencil right through the zip-lock bag.
Repeat the step by poking a few more sharp pencils through the bag. Observe what happens.
How does it work?
Despite poking numerous though the zip lock bag, the water does not leak. This happens so because zip lock bags, like other plastic bags, are made of polymers. A polymer is a substance that is made up of similar kind of molecules or blocks that are bonded together. When poked with a sharp pencil, the molecules bond together near the holes, preventing the water from leaking.