Stick With It – Put Your Duct Tape To The Test!
You may have heard of the space shuttle Apollo 13, or seen the movie about the amazing survival of the ship’s crew after an explosion aboard the ship. What you may not know, is that duct tape helped save the lives of the Apollo 13 crew! NASA had to figure out a way to keep the 3 crew members alive in a tiny lunar module that was only meant to hold 2 people for 36 hours. They instructed the crew to build life-saving air filters using cardboard, plastic bags, space suit parts and – you guessed it – duct tape! The same tape that you use in projects around the house was also used to save lives on a space ship!
In this activity we’re going to explore how duct tape works – and what can make it stop working.
This activity is not appropriate for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.
You probably use tape all the time, but have you ever wondered how it works? Why doesn’t it feel wet, like glue? What makes some tape stronger or weaker? For this activity, we need to understand how tape works!
Household glues like Elmer’s and super glues are liquid when you apply them, then they go through a chemical change and harden to glue things together. Tape works completely differently – there are no chemical reactions! The stickiness of duct tape (and most other strong household tapes) are in large part the result of 2 physical properties, known as wetting and Van der Waal’s forces.
Wetting is a word that we use to describe how effectively an adhesive can penetrate (or sink into) the material it is applied to. Imagine a drop of water on a paper towel, and a drop of water on a piece of wax paper. Water dropped on the towel will sink into, and penetrate, the paper towel. Water dropped on the wax paper will form a water droplet, and will not penetrate the wax paper. Materials that are good at wetting can penetrate into the pores of the materials they’re applied to, much like the water into the paper towel.
Believe it or not, the adhesive on your duct tape is good at wetting. When you push a piece of tape down onto a piece of paper, you help the molecules on the sticky side of the tape penetrate into the surface of the paper.
Once the adhesive molecules have penetrated the surface of the paper (or other surface!), Van der Waal’s forces come into play. These are weak attractions between molecules that normally might not be attracted to each other. Because of the careful arrangement of these molecules in the tape, the tape molecules are able to form physical bonds with the paper molecules. The tape molecules also cohere (stick to each other), and as a result, tape can hold together and stick to, a huge variety of important items!
Extra: Repeat the activity, sticking the tape to a non-stick pan. Be sure to ask for permission first! Add a row to your table to record the results!
Extra: Experiment with other types of tape. Are some more sensitive to water, or temperature than others? Do some hold better than others?
Tip: You can remove any residue left by the tape using olive oil, or an olive oil soaked paper towel. Allow the olive oil to saturate the residue for at least 15 minutes, then scrub it off using a sponge.
Observations and Results
During this activity, you should have found that the stickiness of your tape depended on two general factors; 1. The condition of the tape, and 2. The surface where you were attaching the tape. While the tape stuck firmly to the glass pan, when the tape was wet or frozen it was significantly less sticky compared to your control tape. In addition, when the you stuck the tape to wax paper, it did not stick as well as it did to the glass pan.
So let’s start with the conditions of the tape itself, why doesn’t tape work when it’s wet? Tape loses its stickiness when the adhesive molecules in the tape become wet. When this happens, the water acts as a barrier to wetting (so the adhesive molecules can’t sink into the glass pan) and also prevents the physical bonds from forming between the tape and the pan. The water acts like a wall between the tape and the pan, they can’t get together!
Freezing the tape also decreased it’s adhesive wetting capacity. Again, imagine a few drops of liquid water dropped onto a paper towel, compared to an ice cube dropped onto a paper towel. The liquid water will penetrate the paper towel much more quickly and effectively than the ice cube. Similarly, the adhesive molecules in the tape, when frozen, cannot penetrate the other surfaces as well, so the tape can’t get a firm ‘grip’ on the things you want it to stick to.
In the case of wax paper, the tape didn’t stick as well as it did to the glass pan, but this time it was because of the wax paper. Go back and think about the water drop on the paper towel, compared to the wax paper. Just like the water drop can’t penetrate the wax paper, neither can the tape! Wax paper blocks most materials from wetting, which makes it great at repelling water, food, and in this case, tape!
More to Explore
Megan Arnett, PhD, Science Buddies
Science Buddies |
Wetting, Van der Waal’s forces, adhesion
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