timer program

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PHY 242

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

** TIMER program_labelMessages **

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30 min

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Operating the TIMER program

It is easy to operate the Timer program. All you have to do is click on the button labeled Click to Time Event.

Click that button about 10 times and describe what you see.

I see a data table with 3 columns, the first being 1-10.

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Now click on Initialize Counter, which will clear all the data from the timer window. Click the mouse as fast as you can until the TIMER window fills up. Be sure you get at least 20 time intervals.

If you miss a click, try again. Keep trying until you get at least 20 quick-click intervals without a missed or delayed click.

Copy your data starting in the next line:

1 241.1172 241.1172

2 241.2813 .1640625

3 241.4297 .1484375

4 241.5938 .1640625

5 241.7422 .1484375

6 241.9219 .1796875

7 242.0859 .1640625

8 242.2656 .1796875

9 242.4297 .1640625

10 242.6016 .171875

11 242.7656 .1640625

12 242.9375 .171875

13 243.1094 .171875

14 243.2969 .1875

15 243.4688 .171875

16 243.6484 .1796875

17 243.8203 .171875

18 244 .1796875

19 244.1875 .1875

20 244.3672 .1796875

21 244.5469 .1796875

22 244.7031 .15625

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You got at least 20 time intervals. Based on your data what was the average of the first 20 time intervals? Note that you could get this average by averaging the first 20 intervals. My first few intervals were .15625, .15625, .1875, .171875, etc; I could just add up the first 20 intervals and divide by 20 to get the average. However there is an easier and quicker way to get the result, so use the easier way if you can. NOTE: Spreadsheet calculations and other methods that disguise the process of finding the average are not valid answers to this question. Spreadsheets are perfectly legal for most data analysis, but not in this experiment.

Give your result, number only, in the first line, and starting in the second line explain how you got it.

average of quick-click intervals:

explanation: I added up the numbers and divided by 20 to get 0.17. I started at entry 2.

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When I did this activity the first few lines of my data were as follows:

event number clock time time interval

1 11.67188 11.67188

2 11.875 0.203125

3 12.0625 0.1875

4 12.20313 0.140625

5 12.375 0.171875

6 12.54688 0.171875

7 12.73438 0.1875

8 12.92188 0.1875

9 13.10938 0.1875

10 13.28125 0.171875

11 13.4375 0.15625

It looks like the same intervals keep popping up. For example .1875 seconds occurs 5 times out of the first 10 intervals, .171875 seconds occurs three times, and .203125 seconds, .140625 seconds and .15625 seconds each occur once.

A frequency distribution for my time intervals would be as follows:

time interval frequency

,140625 1

.15625 1

.171875 3

.1875 5

.203125 1

What different time intervals did you observe in your first 20 intervals, and how many times did each occur? List below the different time intervals you observed and the number of times each occurred. List from the shortest to the longest interval, and use a comma between the time interval and its frequency. For example my data above would be listed at

.140625, 1

.1565, 1

.171875, 3

.1875, 5

.203125, 1

The above list is called a frequency distribution. Be sure you make note of this terminology.

Your list should be in exactly the above format, with no other symbols or characters.

Your list (i.e., your frequency distribution):

.148, 1

.156, 1

.164, 5

.172, 5

.180, 6

.188, 2

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You are welcome make any comments or ask any question about the process so far.

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On the 10 intervals I've shown you, do you really think I managed to get a time of .1875 seconds, accurate to 4 significant figures, on half of the intervals? If you do, I'm grateful for your confidence but I'm just not that good. No human being has that much neurological and muscular control.

So why do you think the TIMER program reported that time so frequently? Why weren't there times like .1830 seconds, or .1769 seconds? Does this mean that the TIMER program is flawed? Does that mean it's useless?

Why did the TIMER report .1875 seconds multiple times; your conclusions about the program:

The program may round a certain way which causes entries to be repeated.

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Here are a few more lines of data, with an added column showing the difference between each time interval and the next.

clock time time interval difference from one time interval to next

9 13.10938 0.1875 -0.01563

10 13.28125 0.171875 -0.01563

11 13.4375 0.15625 0.03125

12 13.625 0.1875 -0.01563

13 13.79688 0.171875 0.015625

14 13.98438 0.1875 0.015625

15 14.1875 0.203125 -0.03125

16 14.35938 0.171875 -0.01563

17 14.51563 0.15625 0.03125

Take a good look at that last column and tell us what you see in those numbers, and what this tells you about the TIMER program:

It looks like the program only ends in digits of 3 or 5.

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Now initialize the TIMER once more, and take a series of 10 relaxed breaths. Every time you start to inhale, hit the TIMER button.

My results for the first 7 complete breaths are as follows:

series of relaxed breaths

event number clock time time interval difference between time interval and next

1 1569.734 1569.734

2 1582.75 13.01563 0.32812

3 1596.094 13.34375 3.90625

4 1613.344 17.25 2.70313

5 1633.297 19.95313 1.35937

6 1654.609 21.3125 4.23438

7 1680.156 25.54688 2.15625

8 1707.859 27.70313

I didn't go on because the time between my breaths kept increasing, and I was afraid if I relaxed any more I might stop breathing altogether. It's going to take either more statistical analysis to determine whether that's a real danger, or a little common sense.

Report your results by just entering your time intervals, one to each line, in the box below. If I was entering my results I would enter

13.01563

13.34375

17.25

19.95313

21.3125

etc.

Enter your results in the same format:

4.820313

4.15625

4.820313

4.351563

3.617188

3.507813

5.773438

2.726563

3.3125

5.08594

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If you have any comments please insert them here

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Most likely you did not observe the same exact time interval twice, and if you did it did not happen nearly as often as when you did the fact clicks.

Why do you think this is exactly what we would expect?

When you are clicking as fast as possible there is a much higher chance of repeating since there is a minimum resolution to the program.

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Which of the following statements do you think is the most accurate?

a. The TIMER program is capable of determining the time between two events accurately to within about .1 second.

b. The TIMER program is capable of determining the time between two events accurately to within about .01 second.

c. The TIMER program is capable of determining the time between two events accurately to within about .001 second.

d. The TIMER program is capable of determining the time between two events accurately to within about .0001 second.

Enter your answer and your reasoning below:

I would say d since it appears that there are at least 4 significant figures reported in the result.

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@&

`` If you have a 'clicker' that clicks every 1/3 of a second, and count those clicks to time the interval between two events, you will get possible time intervals of 1/3, 2/3, 3/3, 4/3, ... seconds. In decimal form these intervals could be expressed as .333333, .6666667, 1, 1.333333 second.Just because the decimal equivalents can be expressed to several decimal places doesn't mean that all the figures in the result are significant.So the number of decimal places in the reported results is not necessarily correlated to the accuracy of the instrument.

*@

If you don't have a spreadsheet you should be able to easily access a free spreadsheet in order to do this last step. If you don't have time right now you can do this part later, and submit just a copy of this question and your response, using theQuestion Form .

If you don't know what text editor comes with your device (for Windows this would be Notepad), you should simple search the Web under 'text editing for ****' where **** is your device.

Note that this course is not intended to be run from a handheld device. Screens are too small to clearly see the necessary amount of content. However if either version of the TIMER runs on your handheld device and that device allows you the necessary functionality, it's fine to use it.

Note that the TIMER.exe program can save your data in a format that can be read by a spreadsheet (the TIMER applet cannot do so). This will be very handy in the future, so take a minute and do the following:

If you are using the TIMER.exe program:

1. Click on the button at the lower right of the TIMER form, entitled Click to File Data.

2. A box will pop up allowing you to include an identifying message. You should generally choose to include such a message; for the data presently on your timer that might be 'series of regular breaths time at beginning of inhalation' or something similar. Type in whatever you think would serve as a good identifier for this data and OK that box.

3. A typical Save As window will appear. Decide where to save your data and what to call it, and proceed to save it. The program will save the file as a comma-delimited text file.

4. Open your spreadsheet program (typically Excel) and choose File > Open. Browse to the folder in which you just saved your data. Below the File Name line will be a File Type line; set this either to Text Files or All Files so your file will appear. Open it.

5. A series of windows will typically appear. In the first window make sure the file type chosen is Delimited, the proceed to the next window.

6. In the second window you will see a series of checkboxes; check the one entitled Comma, in order to select the comma-delimited file, then just click on Finish.

If you are using the TIMER applet you can't do Steps 1-3. In this case:

Copy the contents of the program to a text file, using copy-and-paste. Just highlight the contents of the box, copy and past into a text file. Save the text file using any filename you wish. Then proceed with steps 4-6 above.

Your data should appear in your spreadsheet, and can be manipulated as in any spreadsheet.

Copy a few lines of the data from your spreadsheet below, and indicate what spreadsheet you are using:

2 912.8594 4.820313

3 917.0156 4.15625

4 921.8359 4.820313

5 926.1875 4.351563

I am using Microsoft Excel.

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*#&!*#&!

&#Good responses on this lab exercise. See my notes and let me know if you have questions.

Revision isn't requested, but if you do choose to submit revisions, clarifications or questions, please insert them into a copy of this document, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end).

Be sure to include the entire document, including my notes.

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