Science Buddies: "Ask an Expert"

My daughter has been woking on building an Archimedes Screw for an upcoming science fair. Her initial plan was to build several screwspumps using pvc pipe wrapped with flexible plastic tubing. She wants to test how changing the period of the tubing will effect how quickly can be pumped from a lower reservoir to an upper reservoir. We've gone through great lengths to be sure we are isolating our variable as much as possible. Unfortunately, we cannot get the pumps to work. We've tried changing the diameter of the tubing, changing the slope of the pump, testing the pump with the lower end partial submerged v. completely submerged, changing the speed of the pumps rotation etc.

We're now running short on time, and decided that perhaps we should just do the more simple design given for the Archimedes Screw on sciencebuddies.org. (https://www.sciencebuddies.org/science- ... screw-pump) However, after looking over the design, I'm afraid this version would actually be considered an Engineering Project rather than one that just seeks to practice the Scientific Method? Am I correct in this conclusion?

Hi!

The procedure listed on the Sciencebuddies page can be altered to fit your needs. Keeping the PVC pipe the same length, the speed of rotation, the height of the next reservoir, etc the same, you could change other variables to align with the scientific method.

Correct me if I'm wrong, but I believe that by the period you mean the number of times the tube is wrapped around the PVC pipe. You could change this(while keeping the diameter of the tube the same) and see how much water is transferred in a set amount of rotations or time. On the other hand, you could also change the diameter of the tube(keeping the same amount of wraps around the pipe) and see how much water is transferred in a set amount of rotations or time( or any other way of measuring the efficiency.

Hope this helps and let me know if you have any other questions. I am happy to help. Good luck!

Shivansh

Yes, you are correct about the definition of the period. We tried this morning just changing the period of the smaller plastic tubing and achieved greater success than we've had thus far. It's pretty difficult to maintain the slope of the pump since we just have to hold it. That drives me crazy, but at least it's working. The point of the project was to better understand the scientific method, and inspite of (or more likely "because of") all our difficulities, we are accomplishing that task!

Thank you for your response.