1. For this you’ll need a plastic bag and some sharp pencils.
2. Fill the bag with water and seal the top.
3. Jab the pencils through the plastic bag.
4. See the water does not get out of the bag.
This is because the plastic bag is made out of long chains of molecules called polymers. This gives the bag its stretchy properties. The sharpened pencils slip between the molecule strands without tearing the entire bag.
Believe it or not, the long chains of molecules seal back around the pencil to prevent leaks. Now that’s the "Spear-It" of science!