----- The following copyright 1991 by Dirk Terrell
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 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