365.2422

Leave a comment

Since the new year will soon be upon us, this number is a good one for the engineer. It is the estimation (because it is difficult to measure absolutely precisely), the number of days in a year. Sure, we can be more precise, but for calendar calculations, down to the 10,000th of a day is precise enough for roughing out engineering calculations that will involve longer time frames, such as the cost per year of operating a waste-water treatment facility.

Note that the fraction is why we have leap year every four years. It is almost 1/4 of a day, so adding the day every four years keeps us close to the same start and end of the year, rather than having the seasons shift months if we didn’t have leap years. Of course, we haven’t even begun to discuss the slowing of the earth’s rotation over time. Maybe we will save that for a later post.

Engineers like precision. Instead of a year being 365 days, or even 365 1/4 days, think about a more precise 365.2422 days.

72

Leave a comment

As engineer, I have been trained in many things that some consider not so engineer-ish, but actually are. Economics is one of these. Needless to say, engineers care very much about economics. Frugality is our middle name, or at least one of them. Today’s number comes from economics, and engineers learned of it in a course called something like “Engineering Economics.”

72 is a great number to use for quick calculations, and since engineers are always tending to run numbers in their heads, then 72 is a good number for the engineer. The rule of 72 simply states that for percents of compounding interest, divide the interest rate into 72 and you will roughly get the number of years it takes to double the number (e.g. money invested). So, at 8% interest, $100 would turn into $200 in 72/8 = 9 years.

This is just an estimation and if one uses an interest rate that is very low or very high, then the accuracy of the estimation is, in engineering language, “not as good”. But for quick calculations, 72 works fine. Some may say there is a rule of 70 or 69, and they may yield better results at certain interest rate ranges, but these are estimations, people. Just use 72. It has a lot of numbers that divide into it evenly, and gives fairly close results, for estimations.

72 is a number that has power for the engineer because it 1) is good for running numbers in your head, 2) deals with money, 3) is divisible by a number of numbers, and 4) is just plain useful.

Now, I just have to find an investment that pays 8%, with no risk.

144

Leave a comment

Yet another number that represents, for the engineer, how a non-metric system of measures simply does not make sense is 144. It should be stated that although, technically, this number is not directly tied to the pitiful English system to which the United States nonsensically adheres, the fact that we have a number like 144 as a unit for ordering a number of an item, points out the need for a base ten system of weights, measures, and numbering.

144 is a number that is a “gross” of something. It is a dozen dozen. So, if 12 is not a bizarre enough number to use as a unit, we somehow have decided to make it more complicated by multiplying it by itself, by squaring it – 12 x 12, or 144. We end up squaring the illogical number, but instead of that making it make sense, it only makes it more convoluted.

There are times that the approach of the engineer may get complicated and caught up in calculating and recalculating, and adding in factors of safety, and remeasuring, and on and on. But when it comes to weights and measures, and counting – world, listen to the engineer. Let’s not have any more numbers like 144 as part of our system.

0 (Zero)

Leave a comment

Ah, yes, the ubiquitous number 0 (Zero). This is wonderful number for engineers. We will even explain why without having to resort to zero’s intricate value in its use in base ten, and how zero has been such a great help in weights and measurements – a great help if one uses the metric system, otherwise you are on your own.

Zero is used in so many applications of engineering. Engineers set numerous equations to zero to solve for them. Most notably, if an object or point is in equilibrium, then all the forces acting on it will add up to, you guessed it, Zero. This will be the case for all three directions in a space into which the forces are broken down (x, y, and z). So Zero is essential for analyzing any static object or system. If one wants to make sure air pressure is maintained in a building, then the amount pumped and the amount taken out must be equal, or, put it another way, the sum of the in and out amounts must equal Zero. To maintain a temperature in room or building, the heat added plus the heat lost (which will be negative) adds up to Zero.

The other numbers may make fun of Zero, for being a nothing, a loser, a, well, a Zero. But to an engineer, it is wonderful number and one to be respected.

13.3%

Leave a comment

engineeringdaze.com has some wrap-up thoughts on baseball, now that the World Series just finished the season.
This number, 13.3% is not a number that represents anything to an engineer, except frustration regarding the pure lack of logic of some baseball stats. While watching a playoff game recently, a player was batting and a guy was on second base. The announcers stated that this player got hits 13.3% of the time that a runner was in scoring position. That is all well and good, and, as an engineer, I appreciate statistics which break down the game and explore different facets of the odds. They could have broken that statistic down for the player to dissect his hitting percent against left- and right-handed pitchers, outdoors versus domed stadiums, at night or in day games, in his first or second or third at bat, if he had a fielding error in the previous ten games or not, or whether they were playing on real or artificial turf. That kind of examination is fascinating to explore.

However, the guy at second only got there after the count was 2-1, by stealing second. The announcers didn’t talk about that. They didn’t state was this guy’s hitting percent was with men in scoring position but only getting there by stealing a base part-way through the batter’s at-bat which would obviously skew the hitting percent seeing as that he would have less opportunities to get a hit.

Here they are, and by “they” I mean the baseball “people”, with all these statistics and they fail to completely inform us of the true odds of what will about to take place. Disappointing? Most definitely. But, I will be OK. Baseball season is over and now I watch football. Which brings me to some illogical statistics from this past weekend…

10

Leave a comment

Tork, caveman engineer, the first engineer in history, make that pre-history, returns for this week on engineeringdaze.com.

 

Tork noticed that when measuring things like the volume of water in the lake, or the distance to the cute cavewoman’s cave, cave people used small numbers first, then when they need to go to a bigger measurement, they used a larger unit, but it was always a strange one. They multiplied the smaller measurement by 8. Why? Because the biggest caveman who always told all the other cavemen what to do had 8 fingers, not ten like Tork had, and most all other cavemen had.

For centuries, people blindly used this painfully difficult system of measurement based on the number 8, while the system Tork developed, based on the number 10, what became known as the Metork system, eventually lost favor with those in control who thought it might be too difficult to change systems.

Oh, how things could have been different.

3

1 Comment

As an engineer, I have a preference for the number 3. This number is so incredibly meaningful and versatile.

Think about this:

There are 3 dimensions in space that make up the component vectors of any vector in that space.

One wants at least 3 quotes for the cost of a product or service in order to have the possibility of getting a sense of a reasonable price.

3 is a great factor of safety. Design anything, then multiply the answer by 3 just to be sure.

And since 3 is a great number for having as the number of reasons that 3 is a great number, then I hesitate to mention any more of them. Suffice it to say, 3 is an engineering number.

Older Entries Newer Entries