Water Wheel Draft

Below is an example of the quality of draft that we expect from this experiment.  I have not had extensive time to proof it, so please excuse any errors.  Hopefully the gist of what we are looking for comes through.  Use this as a model for your draft.  We will work on the discussion section of the paper tomorrow in class.  I would like to have a draft of this paper due Friday October 28.  My intention will be to read it during the day and get comments back to you before you go home, so you can finish it over the weekend.  Please get started on this tonight!

Let me know if you have any questions.

Mr. H

Introduction

To begin our exploration of the physics and mechanics of water, we decided to build a water wheel.  Water wheels have been in use since well before the present.  Water wheels were used in Rome to grind grain in mills.  Wheels were used in China to grind grain, hull rice and crush ore.  In Medieval Europe water wheels were used also to grind grain.  In the Middle Ages water wheels were used commonly for crushing ore and for processing sugar cane, wheat and rice.  Today water wheels are less commonly used, although they are coming back into fashion as power generators.  (I expect you can add more detail to this history part, I just give a brief overview).  

There are three types of water wheels, an overshot wheel, and undershot wheel and a sideshot wheel.  (Can you think of any advantages of any of the designs that you might put into the paper here).  We are going to build an overshot wheel to test some basic ideas of mechanics.  

The two variables that we are going to investigate are work and power.  We defined work as ______, and power as _______.  To learn more about these concepts we built a water wheel and tested its ability to do work.  Using our water wheels, we set out to answer the following questions:

 What is the maximum weight that our water wheel will raise given a constant flow of water?

Does the rate of the flow of water matter for the maximum weight, or rate of wheel doing work?  If so, what is that relationship?

Is there a relationship between raising small weights long distances and large weights small distances?

I expected that:

1

2  What were your expectations for each of these questions?

3

Materials and Methods

To build the waterwheel we used a 2 (or 1) Liter bottle, a cork and a wire to use as the axle.  To start we divided the bottle into thirds so that we ended up with three cylinders, the top, which included the lid, the middle, which was open on both ends and the bottom.  We used the middle section to create the paddles of the wheel, the bottom as the base for the water wheel, and the top section as a funnel to deliver the water to our wheel.  To build the wheel, we took the middle section and divided it up into 8 equal arcs (each being 1/8 of the circumference of the bottle).  Then we took our cork and also divided the circumference into 8 equal sections.  Using a razor blade we cut a line down the length of the cork to a depth of about 5 mm at each of the 8 sections.  Then we carefully placed the sections of the bottle from the middle into the slices in the cork (see diagram*).  Next we took the wire, sharpened one end and threaded it through the center of the cork.  To finish the water wheel, we took the bottom section of the bottle and cut a V out of the edge to allow water to spill out the side (see diagram*).  Finally we pierced a hole into the sides of the bottle, perpendicular to the V, and hung our wheel in the base (see diagram*).  

After our water wheel was constructed we attached a string to the axle with a dixie cup attached to it so that we could add weight (again, see diagram*).  

*I did not draw diagrams, but we expect that you will.

To answer the above questions, we used the following protocol.

Question 1.  

To answer this question we set the height of our funnel at 10 (or 20) cm.  We also used a rate of ____ mL/sec to test the maximum weight.  We measured the rate of flow by pouring 1 L of water through our funnel and recording the time it took to flow through.  We measured ___ times and took the average flow.  Finally to find the maximum weight we did ___ trials adding weight after each trial until our wheel could no longer raise the amount of weight in the cart.  When we reached this limit we weighed the cart.

Question 2.

To answer this question we set the height of our funnel at 10 (or 20) cm.  We used a constant weight of ____ g in the cart and tested the rate of lifting (in cm/sec) and the total height raised using 1000 mL of water.  We varied the flow of the water ___(3)_ times using flows of ____ mL/sec, _____ mL/sec and ____ mL/sec (repeat for actual number of trials).  We recorded the height that the weight was lifted and the rate at which it was lifted.

Question 3.

To answer this question we used a weight of ____ g in the cart and a flow of ____ mL/sec.  Then, using a constant volume of _______ mL we measured the height (cm) and rate (cm/sec) that a small weight (____g) and a large weight (____g) were raised by the wheel.  

Results.  (notice that there is no interpretation here, just a record of what we found)

Question 1.

We found that at a rate of _____mL/sec that our water wheel was able to raise ____ g.  

Question 2.

We found that with a flow of ____ mL/sec that our wheel raised ___ g an average of _____ cm at an average rate of ____ cm/sec.  We found that with a flow of ____ mL/sec that our wheel raised ___ g an average of _____ cm at an average rate of ____ cm/sec..  Finally, we found that with a flow of _____ mL/sec that our wheel raised ____ g an average of _____ cm at an average rate of ____ cm/sec.

Question 3:

We found that with the same flow of water at a rate of _____ mL/sec that it raised a weight of (small mass) g an average of _____ cm at an average rate of ______ cm/sec.  We also found that with the same rate that it raised a weight of (large mass) g an average of ______ cm at an average rate of ______ cm/sec.

Discussion:

We will work on this together in class tomorrow.