Screw Ups and Downs
Poor screws. They have a bad reputation. After all, “screwing up” means “making a mistake.” But screws are actually very useful simple machines.
The Back Story
- A screw is an inclined plane that is wrapped around a central axis. Most screws, like those pictured above, are used to hold things together. Screws have many other uses as well.
- Watch this clever student video to see some other examples of screws and how they are used:
Can You Apply It?
At the links below, learn more about screws and see additional examples of screws. Then answer the questions that follow.
- Describe the screw.
- State two general uses of screws.
- Describe the screws in the pictures below, and explain how the screws are used.
Credit: Richard KochSource: http://commons.wikimedia.org/wiki/File:Spiral_Staircase_in_the_Presbytere_New_Orleans_1934.jpgLicense: CC BY-NC 3.0
Credit: Scott EhardtSource: http://commons.wikimedia.org/wiki/File:Crest_toothpaste.jpgLicense: CC BY-NC 3.0
Credit: BrianiacSource: http://commons.wikimedia.org/wiki/File:Screws.jpgLicense: CC BY-NC 3.0
- The device sketched below is called Archimedes’ screw. It is used to draw water out of a body of water such as a pond. Based on your knowledge of screws, explain how Archimedes’ screw works.
5. You’ll have a better understanding of the screw and how it is related to the inclined plane if you make a model screw. Do the activity at the second link above. Then answer the questions listed at the bottom of the Web page under “Things to think about during the experiment.”