#$&*
I am not sure that I completed this part of the assignment correctly. I feel as if my answers are a little vague. I tried to give as much information that I felt I could adequately provide. Please let me know if I need to come up with additional information. "
@&
I'm asking some fairly sophisticated questions here, and at this point of the course I don't expect deep answers (though sometimes I do get them).
The main point here will be getting you to think about these issues.
*@
"Most queries in this course will ask you questions about class notes, readings, text problems and experiments. Since the first two assignments have been lab-related, the first two queries are related to the those exercises. While the remaining queries in this course are in question-answer format, the first two will be in the form of open-ended questions. Interpret these questions and answer them as best you can.
Different first-semester courses address the issues of experimental precision, experimental error, reporting of results and analysis in different ways and at different levels. One purpose of these initial lab exercises is to familiarize your instructor with your work and you with the instructor 's expectations.
Comment on your experience with the three lab exercises you encountered in this assignment or in recent assignments.
*********************************************
Question: This question, related to the use of the TIMER program in an experimental situation, is posed in terms of a familiar first-semester system.
Suppose you use a computer timer to time a steel ball 1 inch in diameter rolling down a straight wooden incline about 50 cm long. If the computer timer indicates that on five trials the times of an object down an incline are 2.42sec, 2.56 sec, 2.38 sec, 2.47 sec and 2.31 sec, then to what extent do you think the discrepancies could be explained by each of the following:
• The lack of precision of the TIMER program.
To what extent to you think the discrepancies are explained by this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
The difference from time 1 to time 2 is: 2.56 seconds-2.42 seconds= 0.14 seconds, the difference in time two and time 3: 2.56-2.38= 0.18 seconds, the difference in 3 and 4 times: 2.47-2.38= 0.9 seconds, and the difference in time 4 and time 5 is: 2.47-2.31 = 0.16 seconds. It could be that the timer program is not initiating or stopping the timer when the user is pressing the “initialize” button. Seeing that we are not in a controlled environment, there is going to be a margin of error
#$&*
• The uncertain precision of human triggering (uncertainty associated with an actual human finger on a computer mouse)
To what extent to you think the discrepancies are explained by this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
I think that this factor would be more responsible for discrepancy. I think that there is a delay in our brain telling our finger to press on the mouse and when our finger actually clicks on the mouse. I think that the brain sends out the message, but there is an elapsed time that passes before the finger gets the signal to actually press the mouse button. There could also be delay from the time one’s finger hits the mouse, and the time registers on the timer program.
#$&*
• Actual differences in the time required for the object to travel the same distance.
To what extent to you think the discrepancies are explained by this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
I am sure that there are going to be variable affecting the travel of the ball down the slope mentioned above. I think of the air flow changing in a room. I’m not sure this would be enough to change the speed of the ball but it’s something that should definitely be taken into consideration. When a person looks at the differences in the times listed above, they are not huge differences. The longest difference in time was 0.18 seconds. If this experiment was performed in a controlled environment, the test results should essentially be the same every time in my opinion.
#$&*
• Differences in positioning the object prior to release.
To what extent to you think the discrepancies are explained by this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
Unless the ball was placed in the exact same spot each time, it would affect the amount of time required for the ball to travel down the slope. One millimeter of difference in the placement further back would slow the ball down, and if the ball were placed further forward, this would increase the rate at which the ball traveled down the slope.
#$&*
• Human uncertainty in observing exactly when the object reached the end of the incline.
To what extent to you think the discrepancies are explained by this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
This factor would also affect the timing of the ball rolling down the slope. Unless there is a specific mark on which the user should trigger the timer program, there is room for error.
#$&*
*********************************************
Question: How much uncertainty do you think each of the following would actually contribute to the uncertainty in timing a number of trials for the ball-down-an-incline lab?
• The lack of precision of the TIMER program.
To what extent to you think this factor would contribute to the uncertainty?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
If the timer program is not precise, it would certainly cause error in the results obtained. It would be hard to predict an amount of uncertainty when we are not sure how un-precise the program is. I think that all variables have to be considered to determine the uncertainty of this experiment. (for example: one could not just consider the precision of the timer program, the entire set of variables would create uncertainty)
#$&*
• The uncertain precision of human triggering (uncertainty associated with an actual human finger on a computer mouse)
To what extent to you think this factor would contribute to the uncertainty?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
This would again be the largest concern. Each individual is going to perform an experiment at a different rate. My synapses may fire more precisely than another individual or vice versa. In my humble opinion, I would put more emphasis on this variable than any other, due to the high rate of human error in general.
#$&*
• Actual differences in the time required for the object to travel the same distance.
To what extent to you think this factor would contribute to the uncertainty?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
Again, it would be difficult to place an amount of uncertainty on this particular variable. Unless one is performing an experiment in a controlled environment, there will be many variables that will affect the time required for the ball to travel the same difference.
#$&*
• Differences in positioning the object prior to release.
To what extent to you think this factor would contribute to the uncertainty?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
I believe that this particular variable would be equivalent to the variable with finger firing. This would again come down to the chance of human error. We are humans and we are going to make mistakes, it’s inevitable. With that being said, it would be impossible to start the ball from the exact same spot three different times.
#$&*
• Human uncertainty in observing exactly when the object reached the end of the incline.
To what extent to you think this factor would contribute to the uncertainty?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
This variable would be placed in the same category with finger firing and object starting. In the case of human error, this would be one of the variables that could be easily misinterpreted. One may think that it looks like the ball is stopping in the same place, but it would be extremely difficult if not impossible to have the ball stop in exactly the same place every time.
#$&*
*********************************************
Question: What, if anything, could you do about the uncertainty due to each of the following? Address each specifically.
• The lack of precision of the TIMER program.
What do you think you could do about the uncertainty due to this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
If the timer program were the issue, another version could be considered. One could research options for timer programs, and pick the one with the most accuracy. The experiment could then be repeated with the new timer program.
#$&*
• The uncertain precision of human triggering (uncertainty associated with an actual human finger on a computer mouse)
What do you think you could do about the uncertainty due to this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
I think that it would be difficult to decrease the uncertainty of this factor. A person could repeat the timing part of the experiment multiple times to “iron out” any glitches. Once the person has become more confident with their finger firing on the mouse, they could do a final run on the timer program.
#$&*
• Actual differences in the time required for the object to travel the same distance.
What do you think you could do about the uncertainty due to this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
This would be a variable that would also be difficult to remedy. The individual performing the experiment would need to make sure that everything is set up the same way every time, and make note of any discrepancies. If there were any discrepancies the experiment should be repeated until there are none.
#$&*
• Differences in positioning the object prior to release.
What do you think you could do about the uncertainty due to this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
Interesting question, I have been trying to figure this out all night. I think that the individual would have to be innovative. There should be some type of mark on the center of the ball used to line it up with the starting point on the track that is also marked. The two “dots” or marking points would be lined up in the exact same spot each time in an attempt to prevent inaccuracies.
@&
Excellent idea.
*@
#$&*
• Human uncertainty in observing exactly when the object reached the end of the incline.
What do you think you could do about the uncertainty due to this factor?
your answer: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
This could be remedied in the same way as the previous uncertainty. A mark could be made on the end of the track so that the ball would be recorded at the same point each time. The experimenter would need to make sure that the same point on the ball made contact with the same point on the track each time in order to prevent inconsistencies.
#$&*
"
@&
You gave excellent answers to these questions. Good insights.
*@