Modeling of Water Flow

1. Measure and record the inner diameter of the lift tube. d=
   
2. Determine the inner radius of the lift tube. r =
   
3. Determine the cross-sectional area of the lift tube. A =
4. Noting that a milliliter is also a cubic centimeter, determine the height that 100 mL of water should rise to in the tube. h =
5. Punch a hole in the tube wall about 1 cm from the bottom of the tube (or as far up the tube as you can with a standard hole punch). Measure 2 cm further up the tube from the hole and mark with a piece of tape. Label this mark as #1 and record the height of #1 as 2 cm.
6. Using the calculated height, h, and starting at the center of the hole, measure increments of 100ml. Mark these with tape and label them #2, #3 and #4.  Record the respective distances from the hole (i.e. 2 cm plus the measured increments).
7. Make a table of 5 rows and 6 columns. In the header row, label each column From, To, 1st trial, 2nd trial, 3rd trial and Average, as shown below.

   From	To	1st trial	2nd trial	3rd trial	Average

8. Seal the bottom of the tube with duct tape, being careful not to seal the punched hole.
9. One person should hold the tube over a sink or catch bucket and plug the punch hole with their finger. Fill the tube with water, roughly 5 cm above mark #2.
10. A second person will use a stopwatch to time how long it takes 100 mL of water to flow from the tube. Release the punch hole to let the water out. Start the stopwatch when the water drains to mark #2 and stop it when it drains to mark #1, at which point you should finger-cover the punch hole once again. NOTE: Your team may want to practice this timing sequence a few times before you begin collecting data.
11. Record the height of the water at mark #2 in the first column under From. Record the height of the water at mark #1 in the second column under To. Record the drain time in the third column of the data table, under 1st trial.
12. Repeat steps 9 and 10 and record the time result under 2nd trial.
13. Repeat steps 9 and 10 again and record the time result under 3rd trial.
14. Average the three time results and record under Average.
15. Fill the tube with water again, this time roughly 5 cm above mark #3. Repeat the process above, but draining from mark #3 to mark #2, recording the appropriate heights and measured times.
16. Fill the tube with water again, this time roughly 5 cm above mark #4. Repeat the process above, but draining from mark #4 to mark #4, recording the appropriate heights and measured times.
17. For the fourth and final trial, fill the tube above mark #4 and repeat the process, but this time, drain from mark #4 all the way to mark #1, recording the appropriate heights and measured times.

You have been collecting quantitative information about the function of your model. A visual description of the model's behavior may also add to your understanding. Try the following:

Fill the tube to the top. Release the punch hole and let the water drain. Describe the shape made by the draining water. How does this shape change as the water flows?