Beautiful Simplicity (part 2)

Don't you think, that there is a beauty in simple solutions? Do you know some beautiful-simple devices?

(pictures from Wikipedia if not stated otherwise.)

1) Hydraulic Ram (Water Ram) -- a device pumping the water up, using kinetic energy of flowing water.

2) Valveless pulse jet motor, -- it is working, even though there are no moving parts: (also look here: http://www.home.no/andreas.sunnhordvik/English/mechanical/valveless_e.htm )

3) Thermoacoustic heat engine / Stirling Motor -- only moving parts are piston, crank and flywheel (Wikipedia has a bit poor pictures, but Youtube has better films: Thermoacoustic Heat Engine)

6) Thermoelectric generator -- converting heat into electricity

7) Air Well -- device that collects water vapour from air and converts into liquid water.

8) Crystal Radio -- powered by energy of radio waves:


Vanilla Ice Immobilizer or Ignore No Symptom During Fault-Finding

Well, one more story from the Internet (I promise, one of last copied):

A complaint was received by the Pontiac Division of General Motors:

"This is the second time I have written you, and I don't blame you for not answering me, because I kind of sounded crazy, but it is a fact that we have a tradition in our family of ice cream for dessert after dinner each night. But the kind of ice cream varies so, every night, after we've eaten, the whole family votes on which kind of ice cream we should have and I drive down to the store to get it. It's also a fact that I recently purchased a new Pontiac and since then my trips to the store have created a problem. You see, every time I buy vanilla ice cream, when I start back from the store my car won't start. If I get any other kind of ice cream, the car starts just fine. I want you to know I'm serious about this question, no matter
how silly it sounds: 'What is there about a Pontiac that makes it not start when I get vanilla ice cream, and easy to start whenever I get any other kind?'"

The Pontiac President was understandably skeptical about the letter, but sent an engineer to check it out anyway. The latter was surprised to be greeted by a successful, obviously well educated man in a fine neighborhood. He had arranged to meet the man just after dinner time, so the two hopped into the car and drove to the ice cream store. It was vanilla ice cream that night and, sure enough, after they came back to the car, it wouldn't start.

The engineer returned for three more nights. The first night, the man got chocolate. The car started. The second night, he got strawberry. The car started. The third night he ordered vanilla. The car failed to start.

Now the engineer, being a logical man, refused to believe that this man's car was allergic to vanilla ice cream. He arranged, therefore, to continue his visits for as long as it took to solve the problem. And toward this end he began to take notes: he jotted down all sorts of data, time of day, type of gas used, time to drive back and forth, etc.

In a short time, he had a clue: the man took less time to buy vanilla than any other flavor. Why? The answer was in the layout of the store.

Vanilla, being the most popular flavor, was in a separate case at the front of the store for quick pickup. All the other flavors were kept in the back of the store at a different counter where it took considerably longer to find the flavor and get checked out.

Now the question for the engineer was why the car wouldn't start when it took less time. Once time became the problem -- not the vanilla ice cream -- the engineer quickly came up with the answer: vapor lock. It was happening every night, but the extra time taken to get the other flavors allowed the engine to cool down sufficiently to start. When the man got vanilla, the engine was still too hot for the vapor lock to dissipate.

Moral of the story: Even insane looking problems are sometimes real.


Non-standard thinking -- The Barometer Story

I have read this story 20 years ago, and when I have found it again, I could not resist adding it to my blog:

The Barometer Story
by Alexander Calandra - an article from Current Science, Teacher's Edition, 1964.

Some time ago, I received a call from a colleague who asked if I would be the referee on the grading of an examination question. It seemed that he was about to give a student a zero for his answer to a physics question, while the student claimed he should receive a perfect score and would do so if the system were not set up against the student. The instructor and the student agreed to submit this to an impartial arbiter, and I was selected.

The Barometer Problem

I went to my colleague's office and read the examination question, which was, "Show how it is possible to determine the height of a tall building with the aid of a barometer."

The student's answer was, "Take the barometer to the top of the building, attach a long rope to it, lower the barometer to the street, and then bring it up, measuring the length of the rope. The length of the rope is the height of the building."

Now, this is a very interesting answer, but should the student get credit for it? I pointed out that the student really had a strong case for full credit, since he had answered the question completely and correctly. On the other hand, if full credit were given, it could well contribute to a high grade for the student in his physics course. A high grade is supposed to certify that the student knows some physics, but the answer to the question did not confirm this. With this in mind, I suggested that the student have another try at answering the question. I was not surprised that my colleague agreed to this, but I was surprised that the student did.

Acting in terms of the agreement, I gave the student six minutes to answer the question, with the warning that the answer should show some knowledge of physics. At the end of five minutes, he had not written anything. I asked if he wished to give up, since I had another class to take care of, but he said no, he was not giving up. He had many answers to this problem; he was just thinking of the best one. I excused myself for interrupting him, and asked him to please go on. In the next minute, he dashed off his answer, which was:

"Take the barometer to the top of the building and lean over the edge of the roof. Drop the barometer, timing its fall with a stopwatch. Then, using the formula S= 1/2 at^2, calculate the height of the building."

At this point, I asked my colleague if he would give up. He conceded and I gave the student almost full credit. In leaving my colleague's office, I recalled that the student had said he had other answers to the problem, so I asked him what they were.

"Oh, yes," said the student. "There are many ways of getting the height of a tall building with the aid of a barometer. For example, you could take the barometer out on a sunny day and measure the height of the barometer, the length of its shadow, and the length of the shadow of the building, and by the use of simple proportion, determine the height of the building."

"Fine," I said. "And the others?"

"Yes," said the student. "There is a very basic measurement method that you will like. In this method, you take the barometer and begin to walk up the stairs. As you climb the stairs, you mark off the length of the barometer along the wall. You then count the number of marks, and this will give you the height of the building in barometer units. A very direct method."

"Of course, if you want a more sophisticated method, you can tie the barometer to the end of a string, swing it as a pendulum, and determine the value of 'g' at the street level and at the top of the building. From the difference between the two values of 'g', the height of the building can, in principle, be calculated."

Finally, he concluded, "If you don't limit me to physics solutions to this problem, there are many other answers, such as taking the barometer to the basement and knocking on the superintendent's door. When the superintendent answers, you speak to him as follows: 'Dear Mr. Superintendent, here I have a very fine barometer. If you will tell me the height of this building, I will give you this barometer.'"

At this point, I asked the student if he really didn't know the answer to the problem. He admitted that he did, but that he was so fed up with college instructors trying to teach him how to think and to use critical thinking, instead of showing him the structure of the subject matter, that he decided to take off on what he regarded mostly as a sham.


Beautiful Simplicity

The Simplicity -- one of most important qualities of properly engineered solution.

I would advise you to read "Programming pearls" by Jon Bentley. This is briliant tutorial -- not only how to create good computer programs, but also how to verify basic project assumptions.

You are not computer engineer? Read it anyway -- you will certainly benefit -- also because fantastic quotations:

Albert Einstein
"Everything should be made as simple as possible, but no simpler"

Chuck Yeager
"Simple, few parts, easy to maintain, very strong"

Antoine de Saint-Exupery:
"A designer knows he has arrived at perfection not when there is no longer anything to add, but when there is no longer anything to take away"

John Roebling (architect of Brooklyn bridge -- asked whether his proposed bridge wouldn't collapse like so many others): "No, because I designed it six times as strong as it needs to be, to prevent that from happening."

One sentence more -- not from "Programming pearls" this time:

William of Ockham (Occam's Razor):
"Entia non sunt multiplicanda praeter necessitatem" (entities should not be multiplicated beyond the necessity)



I would like to share my knowledge with my students, and exchange knowledge with my colleagues.
In my blog, I would like give answer for following questions:
  1. How to be a good engineer?
  2. What are best engineering practices?
  3. What makes some engineers better than others?
  4. Could it be learned/teached?
  5. How to enjoy engineering?
With your help Dear Readers, I will try to answer these questions.