What is Engineering?

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What is Engineering? How does it differ from
science?
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Science DESCRIBE EXPLAIN Parameters ?, ?,
?, s2,?,?, ?, g, ?, H2C5OH, . . . Starting
salary 37.5K (chemist)
Engineering INVENT DESIGN BUILD Parameters
Starting salary 59.5K (chemical engineer)
spandex
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Building a house
Cooking dinner
Designing a fuel-efficient car
Siting a biological incinerator
Mathematics/statistics
Physics
Economics
Art
Social studies
Political science
Environmental science
Chemistry
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Education is whats left after youve forgotten
all the facts Ben Franklin Albert
Einstein Oscar Wilde
Don't let schooling interfere with your
education Mark Twain
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Engineering is problem-solving
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Schools, in contrast to the rest of the world,
focus on the acquisition of generalized learning.
Schools aim to teach general skills and
theoretical principles on the assumption that,
once acquired, these skills can then be used in a
wide variety of settings. However, studies of
expert performance indicate that expertise does
not come about primarily from the application of
general skills, but involves the use of
situationally specific, relevant knowledge.
General skills have no actual use in the real
world. Lauren. B. Reznick (1987), The 1987
Presidential Address Learning in School and Out
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What is learning?
Synthesizing theory and knowledge in order to
solve problems Not just theory out of
context--the what. But also the why, when,
and under what conditions the theory may be
invoked to solve a problem. Learning is also
discovering what doesnt work.
". . . a failed structure provides a
counterexample to a hypothesis and shows us
incontrovertibly what cannot be done, while a
structure that stands without incident often
conceals whatever lessons or caveats it might
hold for the next generation of engineers."
Henri Petroski, To Engineer Is Human
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Some vehicles for learning
Problems out of chapter Assignments that
involve efficiency, cost, functionality,
accuracy Back-of-the-envelope problems Fermi
questions Experiments to deduce underlying
principles Hands on--laboratories, virtual
laboratories, projects Written and oral
presentation
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Assign projects
1) Properties of materials
2) Materials laboratory
3) Theory of structures
4) Design a bridge to specification
5) Build it
6) Test it
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If you have to lecture. . .

• Dos
• Introduce each topic or subtopic by posing a
  problem
• Suppose we need to devise a robot that moves
  toward light. . .
• Suppose we want to separate fat from gravy for a
  Thanksgiving dinner. . .
• Suppose we want to bid on a tree as material for
  a toothpick factory. . .
• Suppose we need a bridge to support the weight of
  a car. . .
• Suppose we would like to deduce the period of a
  pendulum. . .
• Continually ask why
• Why do we want to do this?
• Why do we care?
• Why digital instead of analog?
• Why binary instead of decimal?

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If you have to lecture. . .

• Dos (cont.)
• Ask the complementary question Why not?
• Why not use Elmers glue (or a glue gun) on
  spaghetti bridges?
• Why not measure the weight of a single penny on a
  postal scale?
• Why not use titanium to build bridges?

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If you have to lecture. . .

• Dos (cont.)
• Ask what?
• What tools/principles can we use on this problem?
• finding forces in members attached to a pin joint
  on a stationary structure
• separating alcohol from water
• improving the accuracy of a measurement
• What are the conditions under which XXXX
  will/will not work?
• Can we have a stone lintel that spans 20 feet?
• When will a model yield characteristics of its
  full-scale counterpart?
• What does it mean if the mass entering a control
  volume does not equal the mass leaving a control
  volume?

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If you have to lecture. . .

• Dos (cont.)
• Give examples and counter examples
• Give reasons for each step in solving a problem
  (the solution is less important than the strategy
  for approaching it)
• Pose sub-problems, i.e., what if?
• Relate to other fields
• mass conservation vs. Kirchoffs laws
• heat flow vs. electron flow vs. particle
  diffusion (gradient transport)

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If you have to lecture. . .

• Donts
• Dont present theories/calculations without
  context
• Dont use ambiguous or loosely defined terms
• Dont give plug and chug problems (maybe its
  OK occasionally)
• Dont present topics without placing them within
  a bigger picture

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A Problem Describe three entirely different (but
practical) ways for determining the area of the
darkened region to within 0.1. Pick one. Then
deduce the area (in cm2).   Would a different
method give a more accurate result with less
effort? Explain. Might one method be better for
rough estimates, another better for precise
estimates. Explain. Does the effectiveness of
your methods depend on the shape of the figure?
Explain.
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Some possibe answers   1) Superpose a
finely-spaced grid over the figure and count
squares  2) Cut out the figure and weigh it.
Then compare that weight to that of a piece of
paper of known area. If the weight is too small
to be measured with an available scale, transfer
the figure to another piece of uniformly-dense
material which is in the range of your scale.  3)
Throw darts (figuratively, of course). Draw a
rectangle (whose area can be calculated) which
completely encloses the figure. Pick random
points within the rectangle and count which ones
fall within the darkened figure. The ratio of
the number of those points within the darkened
area to those within the entire rectangle can be
used to estimate the darkened area. (Monte-Carlo
integration.)    
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More possible answers. . . 4) Divide the
darkened figure into local regions which can be
piecewise integrated numerically.  5) Use a
polar planimetera gadget which mechanically
integrates the area defined by a closed curve.
(How does a planimeter work?)  6) Draw a
rectangle on the darkened region of known area.
Computer-scan the darkened figure. Write a
program to count the number of pixels of the
darkened color. Compare that number with those
pixels within the rectangle. 7) Build a
container whose cross-section is that of the
darkened figure. Fill the container with 1000cc
of water and measure the water level in the
container.