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Why doesn't glue stick to the bottle? |
by Mya Kagan (whyzz writer) >> more about the author
You’ve probably noticed that glue sticks to pretty much everything it touches! So then shouldn’t it stick to its own bottle? What a sticky problem!
Have you ever learned about how glue holds things together? In order to harden and stick, most of the kinds of glues you’re probably used to using have to allow the water in them to dry out (evaporate). To do that, the glue needs to be exposed to air; if it’s not exposed to air, the glue usually won’t dry. So, by keeping glue in a sealed up bottle, there isn’t enough air reaching the glue for the water to dry out and the glue to stick! (On the outside of the bottle, it’s a different story… streaks or droplets of glue will almost always harden and stick.)
Evaporation in Action!
Most of the gooey, white glues you probably use work by allowing the water in them to dry out, or “evaporate.” Once the water is gone, the special chemicals and products remaining in the glue hold together the things they touch!
To see for yourself the way this works, try out a little experiment:
Put a small drop of glue on each of a few different pieces of paper, and then set each different paper in a separate place to dry. For example, set one in front of a fan, one in a closed up shoe-box, and one on a table-top.
Which of your droplets of glue dries the fastest? Most likely, the ones getting the most air (such as in front of a fan) will dry fastest because their water will dry out first, while the ones getting the least air (such as in a shoe-box) will dry last!
Have you ever learned about how glue holds things together? In order to harden and stick, most of the kinds of glues you’re probably used to using have to allow the water in them to dry out (evaporate). To do that, the glue needs to be exposed to air; if it’s not exposed to air, the glue usually won’t dry. So, by keeping glue in a sealed up bottle, there isn’t enough air reaching the glue for the water to dry out and the glue to stick! (On the outside of the bottle, it’s a different story… streaks or droplets of glue will almost always harden and stick.)
Evaporation in Action!
Most of the gooey, white glues you probably use work by allowing the water in them to dry out, or “evaporate.” Once the water is gone, the special chemicals and products remaining in the glue hold together the things they touch!
To see for yourself the way this works, try out a little experiment:
Put a small drop of glue on each of a few different pieces of paper, and then set each different paper in a separate place to dry. For example, set one in front of a fan, one in a closed up shoe-box, and one on a table-top.
Which of your droplets of glue dries the fastest? Most likely, the ones getting the most air (such as in front of a fan) will dry fastest because their water will dry out first, while the ones getting the least air (such as in a shoe-box) will dry last!
- “How Does Glue Work?” NEWTON – Argonne National Library. 2008. Office of Science – U.S. Department of Energy. 30 Dec. 2010
- Wright, Kevin. “Re: Why doesn’t glue stick to the inside of the bottle?” 8 Nov. 2000. MadSci Network. 30 Dec. 2010
- “Why doesn’t glue stick to inside of the bottle?” General FAQ’s. Elmer’s. 30 Dec. 2010
