How To Measure the Height of a Building With a Barometer

This is a very old story I first heard from my high school physics teacher (Mr. Key). The source I read it at is: http://www.quora.com/Humor/What-is-the-geekiest-joke There is something to be learned about rote/formulaic learning and testing in it.

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. 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 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.

I went to my colleague's office and read the examination question: "Show how it is possible to determine the height of a tall building with the aid of a barometer."  The student had answered: "Take a 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."

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 was given, it could well contribute to a high grade for the student in his physics course. A high grade is supposed to certify competence in physics, but the answer did not confirm this. I suggested that the student have another try at answering the question I was not surprised that my colleague agreed, but I was surprised that the student did.

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, but he said no. 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 read:  "Take the barometer to the top of the building and lean over the edge of the roof. Drop that barometer, timing its fall with a stopwatch. Then using the formula H = 0.5g*t squared, 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 many other answers to the problem, so I asked him what they were. "Oh yes," said the student. "There are a great many ways of getting the height of a tall building with a barometer. For example, you could take the barometer out on a sunny day and measure the height of the barometer and the length of its shadow, and the length of the shadow of the building and by the use of a simple proportion, determine the height of the building." 

"Fine," I asked. "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 of the two values of `g' the height of the building can be calculated." 

Finally, he concluded, there are many other ways of solving the problem. "Probably the best," he said, "is to take the barometer to the basement and knock on the superintendent's door. When the superintendent answers, you speak to him as follows: "Mr. Superintendent, here I have a fine barometer. If you tell me the height of this building, I will give you this barometer."  At this point I asked the student if he really did know the conventional answer to this question. He admitted that he did, said that he was fed up with high school and college instructors trying to teach him how to think, using the "scientific method," and to explore the deep inner logic of the subject in a pedantic way, as is often done in the new mathematics, rather than teaching him the structure of the subject.

The article is by Alexander Calandra and appeared first in "The Saturday Review" (December 21, 1968, p 60). It is also in the collection "More Random Walks in Science" by R.L.Weber, The Institute of Physics, 1982.

I'm going to live forever!

Well, maybe not. But, being the prediction making fool that I am, at least 15 years ago I said that with enhancements yet to be discovered (then) I'd make it to age 120, and maybe longer. At least one friend of mine predicted then that he would live forever.

Seems that some scientists are starting to think this way too. How about this quote "For many scientists who know about such things, the question isn’t whether the first person to live forever has been born, but how old they are."

Supposedly those of us that make it another 20-30 years can expect to make it to 125. And, in those 20-30 years we will probably discover things that will make it possible to go even longer - presumably indefinitely. The kicker for many (like smokers - you know who I'm talking to!!) will be to make it the next 20-30 years.

The enzyme discussed in the linked article isn't considered the final solution, and is considered to be a weak attempt - but notably it is the very first product that attempts to slow down or reverse ageing (not expected to be successful in the latter). Note that this is a measure of how long a cell can divide without dying - possibly not what you are thinking of when you think of reversing ageing. :-)

Also posed in the article - current population predictions don't take into account current population not dying. As Stephen Hawking has said, our species will need to get off this planet if we are to continue. If we aren't dying then the only way to stop the population explosion will be to stop having babies - I can't see that as a viable option either. We will need somewhere else to put people!

Ageing article

I've always appreciated the quotes and stories about how hard work perseveres over blind luck. While I don't discount that occasionally real luck comes along at just the right time - I suspect that more often we create our own luck. That perfect job doesn't just come along; you don't just happen to get a great mark on a test; the perfect partner doesn't just happen to be where you went out. Rather, I think you found the perfect job because you were working hard to find it (submitting resumes, searching job ads, networking with the right people); you got a great mark because you did the homework, went to class, and studied; you found your perfect partner because (like the job) you hung out with people you liked - perhaps s/he was doing the same at the same time.

Well now there is a study that shows you can improve your luck. It examined "lucky people" and their attitudes and behaviours, and compared them to those of "unlucky people." The researchers were able to show that lucky people were better at seeing opportunity (and then taking advantage of it. It wasn't that they got more opportunities, just that they were better at recognizing when they did happen. The linked article (here) used one experiment where the subjects were given a task (count the photographs in a newspaper). There was a half page ad with 2 inch type on the second page that said "Stop counting. There are 43 ..." Although the lucky people tended to see this and stop counting, the unlucky people had such a narrow focus (looking for images) that they tended to miss the ad and kept counting.

The studies examined a number of other factors, but one central fact was that tense people have a harder time noticing things - even (maybe especially) when they are specifically looking for those things. Those who are less apt to focus on only one thing will notice more.

The study's author was able to create a "luck school" and teach unlucky people how to be more lucky. They emphasized four principles and tried to teach three techniques to improve them. 80% became "luckier."

Four principles

[Lucky people] are skilled at creating and noticing chance opportunities, make lucky decisions by listening to their intuition, create self-fulfilling prophesies via positive expectations, and adopt a resilient attitude that transforms bad luck into good.

Three techniques

Unlucky people often fail to follow their intuition when making a choice, whereas lucky people tend to respect hunches.

Unlucky people tend to be creatures of routine ... In contrast, many lucky people try to introduce variety into their lives. [see my earlier blog entry on practising change]

Lucky people tend to see the positive side of their ill fortune. They imagine how things could have been worse.

So - if you are unlucky - you can with a little effort become luckier. Try it, what can you lose?

Lastly, some quotes about work and luck:

"Shallow men believe in luck. Strong men believe in cause and effect." - Ralph Waldo Emerson

The harder I work, the luckier I get. - Sam Goldwyn

When I work fourteen hours a day, seven days a week, I get lucky. - Dr Armand Hammer

It's hard to detect good luck - it looks so much like something you've earned. - Frank A. Clark

I'm a great believer in luck and I find the harder I work, the more I have of it. - Thomas Jefferson

The only thing that overcomes hard luck is hard work. ~Harry Golden

Luck? I don't know anything about luck. I've never banked on it, and I'm afraid of people who do. Luck to me is something else: Hard work -- and realizing what is opportunity and what isn't. - Lucille Ball

Dictionary is the only place that success comes before work. Hard work is the price we must pay for success. I think you can accomplish anything if you're willing to pay the price. - Vince Lombardi

Learn to be lucky. http://www.telegraph.co.uk/technology/3304496/Be-lucky---its-an-easy-skill-to-learn.html

Support Our Troops

"Support our troops" is a phrase that is really beginning to bug me. Not because I don't think the troops deserve support - they certainly do. The phrase bugs me because it is used to justify telling us what to think and it only seems to appear during certain events.

I'll tackle the second issue first. Not all of the fatalities in Afghanistan are combat related. Some have died from the same kinds of things that were killing service members before we ever packed up and headed somewhere with lots of sand. Things like vehicle roll-overs. Before you start to think that I am suggesting these soldiers don't deserve our respect I want to make it clear: THESE SOLDIERS DESERVE OUR RESPECT - the same respect given to their comrades that die from combat. The thing is, the ones that die in-service here in Canada ALSO deserve our respect, no matter the end cause. In these situations the soldier was carrying out his/her duty to our country. The cause of death is not important. What is important is that they died doing their job - one which by it's very nature is a service to the country. But, here is where it gets really hairy - service members were dying on duty long before we ever heard of Al Queda or Taliban or even Saddam Hussein. They will still be dying in service after we have forgotten those names too. So, please respect all of those members that give the ultimate sacrifice in service - no matter the cause, location or time.

Now the issue that really, REALLY, twists my "short and curlies" into a knot: supporting your troops means realizing that a soldiers duties are not always pleasant, and yet understanding that someone needs to do them and that someone needs to feel appreciated in her/his job the way we all do. However, it does not mean that you have to agree with the reasons the soldier has been asked to do those things, nor does it mean that disagreeing with your country's political direction (etc.) disrespects the soldier (some soldiers need to sit up and take notice here as well). Many people though would have you believe that voicing opposition to a current political view that involves sending troops to foreign locations means you don't support those troops.

There are also people that believe they cannot support the troops if they do not believe in the politics. I am here to say that these are mutually exclusive. You can absolutely abhor the reason a soldier is sent on a mission - and yet still support the soldier for doing the job given to him/her. Take your opinion where it should be heard - to the soldier's ultimate masters - the politicians. If you change their minds then they will change the soldier's mission (and s/he will then tackle the new mission). Soldiers are required to obey orders - whether they agree with them or not. The rest of us have a duty to ensure they are given the correct orders.

One last note: occassionaly soldiers go beyond the morally (and legally) acceptable. It has happened in the past (most recently Canadians will remember what happened in Somalia) and will undoubtedly happen in the future. Blind support of the troops is nearly as bad as not supporting them when they are just carrying out their (lawful) orders. Thankfully these situations are not the norm. It is incumbent on the rest of our society to watch for these situations, and occassionally to censure those who go too far.

Cool optical illusion

How many colours do you see? There is orange, magenta, and green. NO BLUE! It is hard to believe but the blue stripe and the green strip are actually the same colour! (And sometimes I see two different magenta/purple/pink colours too - one of which is actually the orange.)

(On my LCD screen it looks pretty freaky if I scroll it quickly.)

Full details available here.