22
0.4Self-Evaluation
The introductory part of a book like this is hard to write, because every
student arrives at this starting point with a different preparation. One
student may have grown up in another country and so may be completely
comfortable with the metric system, but may have had an algebra course in
which the instructor passed too quickly over scientific notation. Another
student may have already taken calculus, but may have never learned the
metric system. The following self-evaluation is a checklist to help you figure
out what you need to study to be prepared for the rest of the course.
If you disagree with this statement...you should study this section:
I am familiar with the basic metric units of meters,
kilograms, and seconds, and the most common metric
prefixes: milli- (m), kilo- (k), and centi- (c).
0.5 Basics of the Metric System
I know about the Newton, a unit of force0.6 The Newton, the Metric Unit of Force
I am familiar with these less common metric prefixes:
mega- (M), micro- (
µ
), and nano- (n).0.7 Less Common Metric Prefixes
I am comfortable with scientific notation.0.8 Scientific Notation
I can confidently do metric conversions.0.9 Conversions
I understand the purpose and use of significant figures.0.10 Significant Figures
It wouldn’t hurt you to skim the sections you think you already know
about, and to do the self-checks in those sections.
0.5Basics of the Metric System
The metric system
Units were not standardized until fairly recently in history, so when the
physicist Isaac Newton gave the result of an experiment with a pendulum,
he had to specify not just that the string was 37
7
/
8
inches long but that it
was “37
7
/
8
London inches long.” The inch as defined in Yorkshire would
have been different. Even after the British Empire standardized its units, it
was still very inconvenient to do calculations involving money, volume,
distance, time, or weight, because of all the odd conversion factors, like 16
ounces in a pound, and 5280 feet in a mile. Through the nineteenth
century, schoolchildren squandered most of their mathematical education
in preparing to do calculations such as making change when a customer in a
shop offered a one-crown note for a book costing two pounds, thirteen
shillings and tuppence. The dollar has always been decimal, and British
money went decimal decades ago, but the United States is still saddled with
the antiquated system of feet, inches, pounds, ounces and so on.
Every country in the world besides the U.S. has adopted a system of
units known in English as the “metric system.” This system is entirely
Chapter 0Introduction and Review