Suzy B Software 2/Suzy B Software CD-ROM 2 (1994).iso/adult_ed/lectures/lect02.txt

Text File | 1995-05-02 | 6KB | 90 lines

 ----- The following copyright 1991 by Dirk Terrell
 ----- This article may be reproduced or retransmitted
 ----- only if the entire document remains intact
 ----- including this header

 Lecture #2   "The Language of Science"

   Scientists are usually visualized as cold, emotionless people who run
around poking and prodding nature, measuring, calculating, and otherwise
"dehumanizing" everything. Again, this stems from the incorrect view that
people have of science as being a collection of facts. I believe that
sciences like physics and astronomy have much more in common with other
human endeavors, such as sculpture and ballet, than people realize. In fact,
teaching a science is very similar to teaching literature. In both cases we
are trying to relate experiences, whether they be the splitting of atomic
beams in a Stern-Gerlach apparatus or the exhiliration of observing the
beauty of unspoiled woodlands. In both instances the experiences are related
through the medium of language. As a science teacher, however, I am at a bit
of disadvantage compared to a literature teacher. When a literature course
begins, the students and the teacher begin on an equal footing when it comes
to the language used. They can immediately exchange thoughts and ideas that
arise from reading a particular piece of writing. When I start a course in
astronomy or physical science, most of the students do not know the language
and I must teach it to them. Having to learn the language of science does
have some positive aspects. The language is truly universal. It is
independent of one's ethnic or geographic origins, or one's social or
political background. In fact, it can serve to bridge gaps between people of
different cultures. The language of science is mathematics and it is
impossible to really have a true understanding of any physical science
without using mathematics.

   The scientific method requires that we do experiments, and experiments
mean measurements, which mean numbers. The famous British astronomer Sir
Arthur Stanley Eddington once said something to the effect that if you can't
put a number on it, it isn't science. So before we move on into some
elementary physics and astronomy, I want to talk a little bit about numbers
and measurements.

   Scientists tend to be a little lazy when it comes to numbers and the
names of things. Listen to one discussion between two people from NASA and
you will wonder whether they are speaking English or not. SRB's, SSME's,
PMT's, LOS, etc. There seems to be a never-ending stream of acronyms.
Basically we try to shorten the time required to express a particular idea.
We do the same thing with numbers for good reasons. In the physical sciences
we deal with very small numbers and with very large ones, and we have
developed a sort of shorthand notation for writing numbers called scientific
notation. We express some large or small number as the product of one number
and ten raised to some integer power. For example, write down the number one
million. How many zeros did you write? You should have six. In scientific
notation one million is written as one times ten to the sixth power. Since I
can't write numbers with exponents on the computer, I will use the usual
notation for computers and write one million as 1E6. The 1 (called the
mantissa) is the multiplier and the E stands for exponent. 1E6 means one
times ten with an exponent of six. 64,326,000,000,000 would be written as
6.4326E13. You can see how scientific notation is more compact that writing
out all those zeros. What about numbers less than 1? In that case the
exponent is expressed as a negative number. For example, 0.0000023 would be
2.3E-6. Practice doing a few of these and ask for help if you are having
trouble.

   When we do experiments we are looking for relationships between various
quantities. The best way to see these relationships is through the use of a
graph where we plot one quantity on the y-axis an another on the x-axis.
When this is done, the relationship is easily seen. For instance, one kind
of plot we use in astronomy is a plot of the luminosity (brightness) of
stars versus the surface temperature. You could make a plot of people's
weights versus their heights. The graph will enable you to see the
relationship between the variables if there indeed is one. Here is an
experiment I would like you to try:

   What you need - a measuring device (ruler, tape measure), several round
objects of various sizes (coins, cans, barrels, etc.) and a piece of graph
paper.

   Measure the diameters and circumferences of the objects (the more
measurements you have the better) and make a table which lists the diameters
and circumferences (make sure that you use the same units for all
measurements, that is, measure everything in inches, centimeters, cubits or
whatever. It doesn't matter which unit you use, just stick to the same one
for all the objects.) Label the divisions on the x and y axes to the same
scale so that all of your measurements can fit on the graph (if your biggest
diameter is 50 inches, then make your x-axis go from 0 to 50). Plot the
circumferences as your y values and your diameters as your x values. I am
assuming that everyone knows how to do Cartesian (x-y) plotting. If not,
please say so. I will be happy to explain. When you have plotted all of the
points, look at the graph and see if you can see any relationship. Is there
some pattern? Do this and let me know what you get.

 Dirk