The NOAA site is easy to use and agrees remarkably with the direct
measurement. The site John referenced uses latitude and elevation data
whereas the NOAA site uses latitude, elevation, plus longitude data.
* * * Student Behavior * * *
In Bluffton (and indeed for most of the USA), we clearly should be using
g = 9.80 m/s^2 if we are rounding to 3 places. I tell this to students
over and over. Yet they keep using 9.81 m/s^2 in all their
calculations. Why is this?
Both their high school text and their college text use 9.81 m/s^2. For
any book problems or examples, if they want to get the same answer as
listed in the book, they need to use 9.81 m/s^2. Therefore, I sure wish
books intended for USA audiences would use 9.80 or 9.8.
I tell students that if they want to use 9.81 for textbook calculations
I guess that is okay, but they should use 9.80 for lab calculations.
However, 9.81 seems so ingrained in their minds that they still use
9.81 for lab calculations.
I readily admit this is trivial in terms of the numerical result,
especially given the sizes of the other errors in the labs. But, the
insistence on using a value that is known to be incorrect certainly
seems bad practice for student scientists. That is what bugs me. Why
do they keep using a number they know is wrong?
Michael D. Edmiston, Ph.D.
Professor of Physics and Chemistry
Bluffton University
Bluffton, OH 45817
(419)-358-3270
edmiston@bluffton.edu