Liar, liar, pants on fire!!

People probably left class today feeling very much confused as to why I called everyone a liar in class when the results of the area of the science department were displayed. Now, don't feel offended if I called you a liar, I do not think ill of you. I do take issue with almost everyone's reported area value. Below I will explain why.

First it has been established that every measurement has uncertainty built into it due to the estimation of the last digit of any measurement. Also, the nature of the procedure introduces error. Since the measuring stick (a.k.a "The Brueckner") had to be slid along the floor end to end over 25 times, it is inevitable that the length measurement will be off by not starting at the precise location that the last measurement ended. This and many other errors could be found in your technique. This is why we never say the "E" word when discussing measurement.

You used two length measurements (which both contained uncertainty and probably error) and multiplied them together. Not only did you multiply the magnitude of each measurement, you also muliplied the error of each measurement by over 25 times. Therefore, any group that reported an area meausurement with more decimal places than what was originally present in the measurement cannot guarantee that calculated value.

These are example from 7th hour:

27.6 B x 32.7 B = 902.52 B^2 --> This should have been reported as 903 B^2
29.63 B x 25.90 B = 767.417 B^2 --> This should have been reported as 767.4 B^2
30.025 B x 26.087 B = 783.262175 B^2 --> This should have been reported as 783.26 B^2

All measurements from the above examples are correct. All groups used the correct amount of precision in the length and width measurements. I will discuss the rule that needs to be followed in class tomorrow, but can you deduce the rule from the values that I indicated to be the correct values to report?