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What are "principles" in science?



Whatever the status of "principles", I think that the statement:

"In a chemical change the atoms in a substance are rearranged
to make one or more new substances."

is so vague as to be meaningless to a beginning student, and to
appear wrong to the expert.

For example, some questions that might be asked:

* Is a phase change (rearrangement of atoms in a substance) a chemical change ?

* Is there a master "substance" whose atoms can be rearranged to make any
other arbitrary substance?

* In the second sentence (not quoted) does composition refer to "arrangement" ?

[ This reminds me of the quotes from textbooks that Mario Iona used to come
up with.]


Al Bachman