Timer Lab

This experiment is self-explanatory. Student report time of completion ranging from 10 minutes to 1 hour, with 30 minutes being the most typical.

Downloading and/or running the TIMER program

If you have a Macintosh computer the preferred timer.exe program might not work (it will if your computer has a Windows emulator), but the alternative Java applet should work just fine.

The program timer.exe should be downloaded to your hard drive and/or flash drive so you have access to it whenever you need it. There is an alternative Java applet, but the .exe option is preferable.

If you are using a Windows PC, or a Mac with Windows emulator, first take a few seconds to run the program q a prelim. As soon as the form opens on your screen, you can close it. Nothing needs to be submitted. The first thing this program does is to create the c:\vhmthphy folder on your hard drive. As an alternative you can also create a c:\vhmthphy folder.

The timer.exe program opens in a small window and can be run side-by-side with other windows applications on your computer (just size the second window so it leaves room for the Timer program).

Run the program now. If it fails to work then try the following, in order:

• If you got the Run-time Error 76, it can be corrected by the step given earlier. That instruction is repeated below:

Run the program q a prelim. As soon as the form opens on your screen, you can close it. Nothing needs to be submitted. The first thing this program does is to create the c:\vhmthphy folder on your hard drive. As an alternative you can manually create this folder.

• If this doesn't work, follow the link COMDLG32 to access simple instructions for fixing the problem. Then run timer.exe .

It is worth 15 minutes of effort to get the program working on your hard drive, after which you will have it and won't need Internet access to run it. It will start up instantly, it runs in a small window, and it has the ability to file your data.

However the Java Applet at the link Timer-Java will work fine for the current experiment, and will do just about everything the timer.exe program will do. The Java applet has a few more or less minor inconveniences and one that's not quite as minor:

• You can't put the Java applet on your hard drive or flash drive, so you have to pull it off the Web every time you want to use it.

• The applet won't file your data. However it will let you copy and paste your data into a text editor.

• If your machine doesn't run Java applets, you would have to set it up to do so (just search the web under 'Java Runtime Environment', which is free and installs easily). This software is pretty standard, and is already installed on most machines.

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.

A total time and an interval.

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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 intervals without a missed or delayed click.

Copy your data starting in the next line:

1 31231.76 31231.76

2 31231.8 .046875

3 31232.13 .3203125

4 31232.16 .0390625

5 31232.5 .3359375

6 31232.55 .046875

7 31233.04 .4921875

8 31233.09 .046875

9 31233.47 .3828125

10 31233.52 .046875

11 31233.85 .3359375

12 31233.9 .046875

13 31234.26 .359375

14 31234.3 .046875

15 31234.66 .359375

16 31234.7 .0390625

17 31235.05 .34375

18 31235.09 .0390625

19 31235.45 .359375

20 31235.49 .046875

21 31235.79 .296875

22 31236.48 .6953125

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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.

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

.1865

Take the 20th number minus the 1st number and divide by 20.

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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

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

11.67188, 1

.203125, 1

1.40625, 1

.171875, 3

.1875, 4

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You may make any comments or ask any question about the process so far in the box below

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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?

The timer may me limited to .1875. as the smallest unit. Good question. The timer isn’t flawed just limited. Nothing is perfect.

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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

The time interval measured is very small.

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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:

4.34375

3.734375

5.171875

4.4375

4.40625

5.46875

5.53125

5.507813

5.195313

4.570313

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If you have any comments please insert them here

I must have small lungs

Time between breaths more a function of habit than anything else. 3-5 seconds is a common average.

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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?

Your hand is more likely to be consistent in a rapid movement. Your breathing is less likely to be consistent. Due to the longer time interval.

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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:

The timer program is capable of determining the time between two events accurately to within about .001 second. The smallest lapse in time were about .0025. which leds me to believe that one could get it down to about one thousandth of a second.

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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:

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.

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:

Series of regular breaths time at beginning of inhalation

event number clock time time interval

1 114.8125 114.8125

2 119.1563 4.34375

3 122.8906 3.734375

4 128.0625 5.171875

5 132.5 4.4375

6 136.9063 4.40625

7 142.375 5.46875

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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?

About 1 hour

&#Your work looks good. See my notes. Let me know if you have any questions. &#

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