template form

initial timing experiment

Your 'initial timing experiment' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.

** template form

Initial Timing Experiment

You may enter any message or comment you wish in the box below:

________________ **

My first seed question has not been posted yet. I sent it a few days ago.

** ________

In this experiment you will use the TIMER program, a hardcover book, a cylinder or some other object that will roll along the book in a relatively straight line, and a ruler or the equivalent (if you don't have one, note the RULERS link on the Assignments page).

The book's cover should be straight and unbent.

The object should roll fairly smoothly.
Place the book on a flat level tabletop. You will prop one end of the book up a little bit, so that when it is released the object will roll without your assistance, gradually speeding up, from the propped-up end to the lower end. However don't prop the end up too much. It should take at least two seconds for the ball to roll down the length of the book when it is released from rest.

Using the TIMER program determine how long it takes the ball to roll from one end of the ramp to the other, when released from rest. Time the object's motion at least five times.

Determine how far the object actually travels as it rolls from one end to the other.

Determine how much higher one end of the book was than the other, and how far it is from one end to the other.
Then reverse the direction of the book on the tabletop, rotating the book and its prop 180 degrees so that the ball will roll in exactly the opposite direction. Repeat your measurements.

In the box below describe your setup, being as specific as possible about the book used (title, ISBN) and the object being used (e.g., a solid glass marble, a small can of tomato paste (full or empty?), a ball-point pen), and what you used to prop the object up (be as specific as possible). Also describe how well the object rolled--did it roll smoothly, did it speed up and slow down, did it roll in a straight line or did its direction change somewhat?

Note: Don't trust this form. Compose your answer in Notepad or a word processor, saving it every few minutes, then copy and paste it into the box. Power could surge, your computer could malfunction, in any of a number of ways the work you put into this form could be lost. Compose it elsewhere and keep a copy.

________________ **

A recipe book was used for the inclined plane. The book measures 28.3cm x 22.3cm x 2cm and is in good condition with no visible warps or tears in the cover. Bibliographical information for the book is:

Stoner, F. (Ed.). (2002). The best of taste of home: The first 10 years. Greendale, WI: Reiman Media Group.

A partial pad of “Post-it” hot pink sticky notes was used to prop up the book. The pad measures 5.1cm x 3.7cm x .5cm. Therefore the inclined plane was raised .5cm at one end.

An empty mechanical pencil that had been wrapped in green florist tape was rolled down the inclined plane. The pencil measures 12.8cm long and the diameter is .9cm. Due to the size of the pencil the starting position was 0.9cm down from the top edge of the book leaving a distance of 27.4cm for the pencil to travel. The pencil rolled smoothly, but often veered towards the pointed end of the pencil.

The pencil was rolled down a ramp for a distance of 27.4cm. A computer timer program was used to measure the time it took for the pencil to cover the distance. The pencil was held in place with the left hand of the examiner. When the examiner released the pencil with her left hand, her right hand clicked the mouse to start the timer. When the pencil reached the end of the ramp the examiner used her right hand again to click the mouse to stop the timer.

** ________

In the box below report your data. State exactly what was measured, how it was measured, how accurately you believe it was measured and of course what the measurements were. Try to organize your report so the reader can easily scan your data and see any patterns that might occur.

________________ **

Time for pencil to roll down book ramp of 27.4 cm from left to right.

1st attempt 2.09375 seconds

2nd attempt 2.671875 seconds

3rd attempt 2.828125 seconds

Average time to cover distance = (1st + 2nd + 3rd)/3 = 2.53123 seconds

Average velocity = 2.53123 sec/ 27.4cm = 0.09238066sec/ 1cm

Time for pencil to roll down book ramp of 27.4 cm from right to left

1st attempt 3.46875 seconds

2nd attempt 3.234375 seconds

3rd attempt 3.3125 seconds

Average time to cover distance = (1st + 2nd + 3rd)/3 = 3.338542 seconds

Average velocity = 3.338542 sec / 27.4cm = 0.121845 sec / 1cm

** ________

Using your data determine how fast the object was moving, on the average, as it rolled down the incline. Estimate how accurately you believe you were able to determine the object's average speed, and give the best reasons you can for your estimate of the accuracy.

________________ **

Average velocity 1st experiment (left to right) = 2.53123 sec/ 27.4cm = 0.09238066sec/ 1cm

Average velocity 2nd experiment (right to left) = 3.338542 sec / 27.4cm = 0.121845 sec / 1cm

Average velocity both experiments = (0.09238066sec/cm + 0.121845sec/cm)/2 = 0.10711283 sec.cm

Very good explanations, and good data.

Note, however, the average velocity is (change in position) / (change in clock time), not the reverse, and the units corresponding to your data will be cm / sec.

I believe the second time the experiment was conducted (right to left) the results were more accurate than the first time (left to right). When the pencil was released from right to left the results had a range of only 0.234 seconds from the longest to the shortest time, while the difference in the results for the first time had a range of 0.734 seconds. This means that the results were all closer to the mean in the second experiment. To give a very accurate estimate on the accuracy of the results one should find the standard deviation of each set of data.

A possible explanation of the discrepancy between the two sets of data is that from right to left the examiner’s fingers were behind the pencil and possible gave some push when releasing, causing the pencil to roll faster. The examiner’s fingers were in front of the pencil when releasing the other direction and possibly did not give as much push.

The accuracy of the experiment is affected by three main variables; the examiner’s hand position, the synchrony between the examiner’s two hands, and the low number of data. Because the pencil was released by hand there could have been some unintended assistance (push) by the hand especially when the fingers were behind the pencil. There is also the inaccuracy of both hands working together in synchrony to release the pencil and start and stop the timer. Finally the experiment should be completed many more times in order to gather more accurate information. Given those variables I believe that the second time the experiment was somewhat inaccurate. However, the range between the two average velocities was only 0.029464 seconds, which is pretty close.

** ________

Devise and concuct an experiment to determine whether or not the object is speeding up as it rolls down the incline. If you have set the experiment up as indicated, it should seem pretty obvious that the object is in fact speeding up. But figure out a way to use actual measurements to support your belief.

Explain how you designed and conducted your experiment, give your data and explain how your data support your conclusions.

________________ **

To test if the pencil is speeding up I click on the timer when it starts to roll, at 9 cm, 18 cm, and 27 cm. Since the distance increments are the same, if the time increments decrease then we know that the pencil is speeding up.

Time for pencil to roll down inclined plane of 27 cm in seconds.

Attempt # 9cm 18 cm 12cm

1 1.09375 0.671875 0.46875

2 0.859375 0.59375 0.6525

3 1.0625 0.65625 0.578125

Each attempt the time decreased between distance increments, therefore the pencil was speeding up.

** ________

Your instructor is trying to gauge the typical time spent by students on these experiments. Please answer the following question as accurately as you can, understanding that your answer will be used only for the stated purpose and has no bearing on your grades:

Approximately how long did it take you to complete this experiment?

________________ **

90 mins

initial timing experiment

Your 'initial timing experiment' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.

** template form

Initial Timing Experiment

________________ **

** ________

________________ **

** ________

In the box below report your data. State exactly what was measured, how it was measured, how accurately you believe it was measured and of course what the measurements were. Try to organize your report so the reader can easily scan your data and see any patterns that might occur.

________________ **

** ________

Using your data determine how fast the object was moving, on the average, as it rolled down the incline. Estimate how accurately you believe you were able to determine the object's average speed, and give the best reasons you can for your estimate of the accuracy.

________________ **

Very good explanations, and good data.

Note, however, the average velocity is (change in position) / (change in clock time), not the reverse, and the units corresponding to your data will be cm / sec.

** ________

________________ **

** ________

________________ **

** ________

You may add optional comments and/or questions in the box below.

________________ **

Very good, and well reported. Do see my note, though, about reversing the definition (velocity is in cm / sec, not sec / cm).

initial timing experiment

Your 'initial timing experiment' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.

** template form

Initial Timing Experiment

________________ **

** ________

________________ **

** ________

In the box below report your data. State exactly what was measured, how it was measured, how accurately you believe it was measured and of course what the measurements were. Try to organize your report so the reader can easily scan your data and see any patterns that might occur.

________________ **

** ________

Using your data determine how fast the object was moving, on the average, as it rolled down the incline. Estimate how accurately you believe you were able to determine the object's average speed, and give the best reasons you can for your estimate of the accuracy.

________________ **

Very good explanations, and good data. Note, however, the average velocity is (change in position) / (change in clock time), not the reverse, and the units corresponding to your data will be cm / sec.

** ________

________________ **

** ________

________________ **

** ________

You may add optional comments and/or questions in the box below.

________________ **

Very good, and well reported. Do see my note, though, about reversing the definition (velocity is in cm / sec, not sec / cm).

Very good explanations, and good data.

Note, however, the average velocity is (change in position) / (change in clock time), not the reverse, and the units corresponding to your data will be cm / sec.