|By Henry Petroski
BECOME GOOD FUTURE ENGINEERS, STUDENTS MUST LEARN ABOUT
1960s are readily remembered as the decade of the Beatles,
the Vietnam War, and the first moon landing. But they
were also years that ushered in less headline-grabbing
cultural and technological changes, such as the way
in which some familiar things are designed and operated.
This was brought home by an article in my local newspaper
that described a popular '60s exhibit mounted
by a nearby rural county museum. There, period snack
items are sold at a replica of a drugstore counter,
with soft drinks available only in bottles having "old-style"
caps that require a separate opener. These have evidently
"confounded some younger patrons" of the
museum, who have grown up with twist-off caps and pull
tabs. It's easy to forget that things that once
were commonplace can seem exotic and mysterious to those
who never experienced them.
When I first began teaching, in the 1960s, slide
rules were beyond comment. It was taken for granted
that every engineering student owned one and knew how
to work it. Ironically, it was the introduction of the
electronic slide rule in the early 1970s that drew attention
to the conventional one—and to its limitations.
Engineering instructors debated the fairness of allowing
the use of the expensive new devices. But while faculty
committees deliberated, students took advantage of the
falling prices of calculators and made the question
Now, of course, slide rules have become puzzling
museum pieces. Imagine handing out "slip sticks"
to a class of first-year students and asking them to
perform a simple calculation. It's possible that
some could not even identify the instrument that was
once the mark of an engineering student, and it is likely
that no one in the class could operate it.
One way to get a class to think about how things
used to be done—and hence to appreciate how and
why today's technology displaced the old—is
to ask what people did before there were the gadgets
that we now take for granted. This gets to the heart
of understanding design and the evolution of technology
of all kinds.
Among the things I have done to introduce the topic
of structural design is to hand my students aluminum
soft drink cans, with the admonition that the students
not open them before we talk about design. Why, I ask,
is the can shaped the way it is, with a domed bottom
and a tapered top? Why is the opening mechanism made
the way it is? Were beverage cans always made this way?
If not, why, when, and how did the now-ubiquitous aluminum
can come to be as it is?
After a while—but before they get warm—we
all open up and enjoy our sodas, while continuing to
discuss the container. Why are the walls of the can
so thin and flimsy? Why does the opening tab stay attached?
How might the design of the aluminum beverage be improved?
The exercise emphasizes that design and engineering
are influenced by much more than just current technology,
and that looking back at the history of things can be
as instructive as speculating about their future. The
computer chip designer Jeri Ellsworth was recently quoted
as saying, "A really good designer needs to know
how the old stuff works."
The environment of the classroom and the world in
which it is embedded is rooted in the past, a fact that
teachers forget at their peril. There can be no real
learning for the future without a sense of connection
between past and present.
Henry Petroski is the Aleksandar S. Vesic Professor
of Civil Engineering and a professor of history at Duke
University. His latest book, Pushing the Limits: New
Adventures in Engineering, was published in September.