How to Prevent Erosion on a Sloped Driveway. How to Hang a Round Rug on the Wall. How to Weave a Navajo Rug on a Loom. We will be happy to hear your thoughts. Leave a reply Cancel reply. Rubber is a polymer formed from chains of molecules. It is flexible because there are not many cross links between the chains to prevent them from moving. Ultraviolet light from the sun and heat breaks up the polymer chains, causing the rubber bands to crack.
Stretching them too far breaks the polymer chains. You can make your rubber bands last longer by keeping them in a cool place out of the light, such as in a refrigerator or basement. Well, rubber, whether natural or synthetic, is a polymer and its chains of molecules are vulnerable to many of the same factors that affect all polymers — ultraviolet radiation , temperature extremes, ozone and oxidation. Rubber that gets regular use will retain its flexibility and molecular properties longer than neglected rubber.
During the manufacturing process, the tire-maker adds a protective compound to the rubber formulation. Use a permanent marker to draw a line on the side of the bottle that is even with the bottom of the rubber band, and label it "hot.
This will cause the water level to rise, so some water will spill out of the holes you poked for the pencil.
If the water is still very hot, the ice cubes may melt quickly. Continue adding ice cubes and stirring gently until the bottle and water feels very cold. What do you think will happen to the length of the rubber band at this new temperature?
Look at the side of the bottle again, so your eyes are level with the bottom of the rubber band. Draw a new line that is even with the bottom of the rubber band and label it "cold. Is this what you expected to happen? Why or why not?
Extra: You can quantify the activity by using a thermometer to measure the different water temperatures and a ruler to measure the lengths of the rubber band. If you take measurements at multiple points for example, hot water, room-temperature water, ice water , then you can make a graph of your results. Extra: Try other methods of heating and cooling instead of using hot and cold water. For example, pour the water out of the bottle, and heat the rubber band with a hair dryer.
Then to cool it, try leaving the bottle in your refrigerator for about half an hour. Do you get the same results when you measure the rubber band? Extra: Try the activity again with different rubber bands.
Do some shrink or lengthen more or less than others? Why do you think that is? Build a Cooler. Get smart. Sign up for our email newsletter.
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