Saturday, July 7, 2012

Heat index and other imaginary numbers

Some imaginary numbers annoy me. Just on principle. 

Like the "heat index." A weather forecaster stands there and pretends that a high temperature added to high humidity equals an even higher temperature. That's simply not true. Wet heat and dry heat are different. Hot and humid can be sweltering, it can be steamy, but it's not like hot and dry. It's the difference between a desert and the tropics. One ain't like the other and inventing a "heat index" don't make it so. 

"Wind chill factor" is another. Where is the wind chill factor when the hot and humid wind is blowing sticky grime onto my glasses? Even in winter, cold and windy is cold and windy. A cold wind does not feel like a colder non-windy day. You can't use a colder temperature to represent cold and windy. One ain't like the other. 

Its not just weather. Some cyclists use their own imaginary numbers. Like "on bike average speed" versus overall average speed. As far as I'm concerned,  if you are riding an event or route with a start and a finish, only the total time it takes to get from the start to the finish matters - anything else is misleading. Not counting off bike time is like saying, I've been awake all week - except for the times I was asleep.  If you stop between the start and the finish, the ride clock keeps ticking - it still counts. Folks should not pretend it doesn't.

Enough with the false comparisons! There I said it. Now I feel better. 

Carry on.

6 comments:

  1. Very well stated Nigel. I agree that rolling average speed is relatively meaningless, so I never bother looking at it or writing it down anywhere.

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  2. Ever listen to "Planet Money?" They start every episode with the Planet Money Index, which is just some number that's relevant in some way to some current event or anecdote they want to tell you. Took me a couple of episodes to catch on.

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    1. Can't say I have. I assume it's a radio show?

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  3. Only time I look at rolling average speed is if I'm riding a familiar route, benchmarked, to see if I actually am getting stronger. A little essentially meaningless numerical reassurance, or the opposite maybe. Actually, now that I've written that total time works exactly the same, since I don't stop. (Whoever said it's ok to think out loud in comments??!?)

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    1. I say its okay to think in comments! and I agree that on a non-stop ride average speed is a valid number.

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  4. A number whose square is less than or equal to zero is termed as an imaginary number. Let's take an example, √-5 is an imaginary number and its square is -5. An imaginary number can be written as a real number but multiplied by the imaginary unit.in a+bi complex number i is called the imaginary unit,in given expression "a" is the real part and b is the imaginary part of the complex number. The complex number can be identified with the point (a, b).

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