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Ever wonder what makes tape sticky? Hank will tell you in this episode of Quick Questions!

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Have you ever wondered how tape works?

Well, if you think the answer is 'by being sticky' you're not thinking hard enough. Sticky tape is what is known as a viscoelastic material, which means that it has properties of both a solid and a liquid. When you leave it alone it stays solid, or turns back into a solid. But when you apply pressure to it, it flows like a liquid filing up any cracks or gaps  in the thing you're sticking it to.The things that you're sticking it to, in case you wanna sound super smart while your hanging up the posters for your junior prom or whatever, is called the substrate. And that same pressure that makes the adhesive act like a liquid also causes it to form weak molecular bonds, called Van Der Waals bonds, between it and the molecules of the substrate. Van Der Waals bonds are what you get when molecules experience electrostatic attraction. See stable molecule are electrically neutral, they don't have a positive or negative charge; but neutral molecules can still be dipoles, meaning that they can have one side with a positive charge and another side with a negative charge. This makes the molecule as a whole act like a tiny magnet and the adhesive in sticky tape is made up of those dipoles. So the pressure you apply when you stick it to your face, forces the molecules of the adhesive and the substrate into close contact, which is when all of those tiny magnets start sticking together. When you stop applying pressure the adhesive goes back to behaving like a solid, which locks it into the substrate, gripping it like a piece of a jigsaw puzzle. Of course when you rip the tape off, you break the Van Der Waals bonds and then you can stick the tape to something else, apply pressure and start the whole process over again. At least until the surface of your tape has to much dust and gunk bound to it to make contact with the substrate anymore. 

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