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Re: [Phys-L] strange things in chem book



These are actually fairly good except that in some cases they do not go far
enough.

A hypothesis is a prediction based on an explanation. It is not just a
guess, but it can be based on a tentative explanation, or it can be based on
an established theory or something in between. And many experiments do not
have a hypothesis because you want to find out what happens, but you have
only a vague notion of what you might find.

A theory is certainly how we think things work, but it is a fairly complete
model. I would call this a bit of a simplification. But sometimes other
words are used to label theories. Quantum theory is called quantum
mechanics. And of course people who wish to denegrate science they don't
like will way "it is only a theory". Here they are conflating a common
definition of theory with the way in which the term is used in scientific
writing. In other words there are 2 definitions which are almost opposites.
This is sort of like what dictators do when they wish to confuse their
opponents and make themselves appear to be good. In other words a common
usage of theory is actually equivalent to a weak hypothesis or conjecture.
So those opposing science should really be saying "It is only a
hypothesis.", but that might be tantamout to admitting their lack of
education.

A law is often a mathematical model such as Boyle's law, Newton's law... It
is essentially a description of how something works without necessarily
referencing a theory, but it can be based on a theory. Laws are not
explanations, and certainly never "proven theories". This latter idea that
a theory became a law when proven was prevalent in many texts in the mid
20th century, but if you look at all the things called laws, they are not
theories. But theories usually contain one or more laws, and can even
"explain" them in terms of each other.

A data table certainly in principle should contain only the raw data, but
there are some ambiguous things here. If you measure something longer than
a meter, you might do it by using 2 meter sticks, so you have to add one to
the other. Is that a measurment or a calculation? I would allow a table to
have raw and calcaulated data together for convenience. So I suppose it is
not a "data" table.

I would say these statements are true, but need a bit of qualification.
Unfortunately the idea that a theory becomes a law has been repreated so
often that people believe it. Laws such as Boyle's law were found
emprically and are not true for all temperatures and pressures, and anyone
can measure a process and find the equation or principle which guides it.
If this equation goes into common usage it may be called a law. Newton did
not call his famous 3 laws laws. There is now a move to call Einstein's
famous E=mc^2 equation a law.

Language definitions are slippery, and in English we do not have language
police to enforce definitions.

John M. Clement
Houston, TX



I am teaching gen chem for the first time in years (high
school). The book says some strange things:
a hypothesis is a prediction with an explanation.
a theory is a how we think things work.
a law is a mathematical model for prediction.
a theory can not become a law.
a data table should only include raw data. it should not
include any calculation, not even subtraction of two collected values.
These statements seem to be a bit odd. Am I alone?

Have a good one.
Thanks for your input.

Paul Lulai.
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