Al Tobias (wat4y) - Office: Gibson S123 & Physics 218, (434) 924-0538
Demonstrations are cataloged according to PIRA Bibliography
PLEASE REQUEST DEMOS WELL IN ADVANCE
Due to Physics Building renovations, the lead time to set up demo requests has increased due to the need to transport equipment across campus. Please be kind and let me know well ahead of time what you need.
Choose a Topic or Enter a keyword to search:
You have selected the following Demos:
Terminal Velocity of Coffee Filters
Purpose:A quantitative example of inertial drag
Procedure:First get a suitable distance to time the falling of the filters. The top of the bench is a good reference, measure the height with a meter stick. Drop a single filter from a height at least a meter above the table so that it is travelling at terminal velocity by the time it reaches the table. Measure the time it takes for the filter to fall from the top of the table to the ground and record the measurement. You'll probably want to take a few measurements and average them. Next, drop 4 filters at once, making sure they are stacked tightly. Make the same measurements as before. the time for 1 filter to drop should be twice that for 4 filters to drop. Since the drag force was increased by a factor of four (4 filters insead of 1), and the speed only increased by a factor of 2, the drag force must be proportional to the speed squared. At least it is consistant with this, you could make more measurements with different numbers of filters to be sure.