explanation: "The secret is to uncover the portion of the balloon where the latex molecules are under the least amount of stress or strain. Now, try piercing the ballon through the center - POP!" - Steve Spangler
Now, try to spear a water filled bag with a pointy pencil! Can you pierce it without creating a leak? Check out Steve Spangler's un-pop-pable bag!
explanation: It's chemistry! "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." - Steve Spangler