Definition: the tendency of solid materials to return to their original shape after being deformed.
History: From A History of the Theory of Elasticity (1886): The modern theory of elasticity may be considered to have its birth in 1821, when Navier first gave the equations for equilibrium and emotion of elastic solids, but some of the problems which belong to this theory had previously been solved or discussed on special principles, and to understand the growth of our modern conceptions is needful to investigate the work of the seventeenth and eighteenth centuries.
Related Learning Ideas:
We are demonstrating this Education.com project today.
First step is to gather all materials for the experiment. This is a relatively simple list:
4 Gummi Worms (Buy a good brand.)
A rubber band (we used one for each worm)
Cut the rubber band to the length of the worm. This was a little tricky, but we managed. We had a lot of extra rubber bands available just in case.
Measure Worm #1. Instead of completing the process 4 times, each of us took a worm. This worm measures 3.75" BEFORE we stretched it.
The kids enjoyed measuring and playing with the worms. They were sad because they could not have the worms afterwards. Braces sure cramp the fun!
The results are in: 1 worm did not gain any length. The rest gained at least a 1/4 of an inch.
So what was the conclusion: Elasticity is the ability of a material to return to its original shape after being stretched. We discovered that the rubber band is perfectly elastic. However, the worms…it depended upon the worm.
SO, this is where Science becomes a blast in our house. (Sometimes, quite literally!) The kids start asking questions…
What would the result be if we changed the temperature?
What if we used a different brand of worm?
Can we cook the worm?
And THAT is just what we did. Don’t worry. I was supervising the whole time. My kids are never allowed to play with fire.
Victim worm#1. This poor worm volunteered to go first. We ran it over the flame for about 10-15 seconds. Then we tested to see how it would stretch. Before the fire bath it would only stretch to 4.5". This time it made it to 10" and *SNAP*. Now we have 2 worms.
That wouldn’t do. So Missy had to prove that it was a defective worm. So
victim worm #2 steps up for the fun.
This time the worm as roasted. I tried to not worry about worm juice getting all over our carpet. Luckily that didn’t happen. (And then I tried not to think about what that implies when we eat said gummi worms)
The results are in. The 4" worm now stretches to a nice 12". And it went back to a 4.25" worm.
So, we concluded that the more pliable/soft, the more elastic. The more ridgid the material, the less elastic.
Disclosure: No worms were harmed or ate in the making of this blog post. They were given a proper disposal in the trashcan.
Join us again next time when we ask the question…
How do you stop a speeding car?