phys11archchallenge17 | Alexandra's Blog

28
Nov
2017

Archimedes Challenge

categories: Grade 11

The Archimedes Screw

The Archimedes Screw which can also be known as the screw pump was invented back in about 287 to 212 B.C (that’s the time Archimedes was alive). It was created by a now famous inventor Archimedes, renowned for his early inventions and principles of his day. Although Greek born Archimedes was raised in the ancient city of Syracuse, now modern day Sicily. When Archimedes was still a young boy he would travel to Egypt, to study in Alexandria, the land once commonly known for its other famous inventor Euclid, but not for very long. Archimedes would learn his passion for inventing while in Egypt and would pursue it when he got back home. Archimedes would flourish in this career making ground breaking inventions of his time, some can even still be seen in modern day. For one of his most coveted inventions to be built it would be an problem that simply needed solving and Archimedes would deliver. The king (Hiero) would ask for assistance with getting the rainwater out of the hull of his ship, that’s when he came up with the idea for the screw. Although the screw didn’t really have any short term implications, it actually improved the lives of many of that time, in the future it can be linked to the cause a ripple effect on those involved. Archimedes first “big” invention was this, and being successful in this led him to create bigger things such as the mirror of death (which would wreak havoc along many foreign ships too come) creating this mass weapon would put an even bigger target on his hometown Syracuse, and eventually it would be raided by the Roman army. Not only did many in his town get killed but so did he, when a soldier saw him carrying mathematical books that looked of importance he killed him then and there. Now it can be seen being used it multiple different ways, mainly for things like sewage and irrigation/drainage purposes, but of course with some modern day improvements.

The Archimedes screw has been used for a long time, with that came many improvements (things like a motor instead of a manual lever, and metal instead of wood). To be explained simply it’s just a big screw inside of a tube, that moves liquid up it, it’s really just an alternative to a bucket pulley system. Its design allowed for any excess product that would fall back down when being used to not go to waste you would eventually be able to get up all the liquid that was there before making it quite efficient, the manual labour was drastically decreased when compared to the efforts of a pulley system. For the concept to work it has to be held at about a 45 degree angle otherwise the liquid would travel down the spiral and not up it (think water slide) because there would be no pockets for the water to stay while spinning up the tube. The reason the liquid travels in these “pockets” up the tube is because gravity always wants to force it into the next dip (bottom of spiral) and so on until it reaches the top of the screw where it will then be dispensed. The physics behind it has to do with the basic laws of gravity and motion, it’s pretty basic the only numbers that really play a major factor how it works is the angle you hold it at, which can be determined once its already built. However when building it you have to take into the account of the size of you spiral it has to fit perfectly into your tube otherwise it might not work you will have to do some measurements and figure out the circumference of the circle (πr^2) to see the radius that you would need for your spiral discs. It can also be related to the potential energy as it spins around the tube it builds up and then it is released as kinetic energy at the top of your tube, they force/work needed is also effected by the coefficient of friction (what materials you used) for example super smooth woods gliding against each other would be easier to spin then a rough plastic scraping along the sides of the tube (like our example).

The lever allowed for less work input from human sources (made it more efficient). The tube is not needed in all adaptations of the Screw but in this version its needed to make it work. You can see how the inside works below, with the water sitting and spinning in the dips of the screw.

Inside works:

Down below you can see the process of us building it, it took a long time for some steps because some of the plastic spiral discs didn’t fit perfectly into the tube so we had to sand them down which took some time that we didn’t think we would have to use for that. Its a basic design so we started with all our materials cut them down to size then we were ready to assemble, here I have pictured the parts used in assembly.