5

June 5, 2012

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The number 5 is a very scary number for engineers. They may not even know it consciously, but it is there – lurking, waiting, about to pounce.

Five represents the number of people that it takes to officially have “an audience”. And, you know what that means. If the engineer has to speak and explain something to 5 or more people, he will consider it, in his mind, to be a PRESENTATION.

This is bad. This is very bad. The engineer may be awkward explaining a point of his work to one other person, two is a bit strange, three is uncomfortable, and four is somewhat unnerving. But once there are 5 people, all bets are off. The engineer goes into presentation mode – badly telling jokes (or what he thinks are jokes), using barely readable charts and graphs, and keeping a monotone level in his voice.

The number 5. If it wasn’t an engineer, I would say that emotions were creeping in.

5 people. That’s an audience.

5 is a number. A scary number.

145

May 29, 2012

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For many engineers, the number 145 is a good number. Most non-engineers (NE’s) may think this is because 145 is a low estimate of the engineer’s IQ – all right, maybe not MOST, but there are surely one or two gullible NE’s.

145 could represent the number of people the engineer found out was going to be at his upcoming presentation, causing him to throw up in anticipation.

145 may represent the number of times the single engineer practiced the “speech” to ask out a girl, until he realized that there was no way he would get through it without writing it down.

145 might represent the number of times the engineer with kids has told them “No” to the frivolous request of wanting to buy a new car, or even a new used one. The ’97 minivan is running great.

But 145 actually is – and here is the exciting part so please stand near my NE friend Tom when he reads this in case he faints – a good estimate for the density of concrete. 145 pounds per cubic foot is what concrete typically is in terms of (English system) density. Sure, if it is reinforced or made denser with additives, it may get up to or over 150 pcf. There are ways to bring it down below 140 pcf. But 145 is a good, sound number to use in any calculation.

In case any of you NE’s out there are on a game show and they show you a cube of concrete one foot in dimension on each side, you will now know the answer of how much it weighs, so that you can move on to the next round. You’re welcome.

70

May 8, 2012

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This number, 70, is very important to any engineer that wants, or, dare I say, needs to get their PE license. It has caused untold angst to many an engineer down through the decades. The reason is that 70 is the number that represents a passing score on the Professional Engineering (PE) exam. Well, sort of.

From reading a fair amount about the scoring process of the PE exam, 70 at least used to be the scaled score that an engineer would have to get to pass. I remember being told this and reading this when I took the PE exam. Now, with equating, the different structure of the exam, the differing approaches of the states that designate passing scores, and numerous other reasons, one thing is extremely clear – no one knows what passing really is and what that 70 represents any more.

So, while an engineer may take the PE exam and desire to score at least a 70, that might mean that the engineer has passed the exam, or it might not. To confuse matters more, the 70 does not necessarily represent 70%, as many might think. With typically 80 points, that would mean getting at least 56 correct to pass the exam, but again, though many believe this to be the case, it is apparently not. The score one receives on the PE exam is a scaled number that is derived, from best accounts of it, by a group of experts locking themselves in a room with the exam and challenging each other to feats of engineering. I’ve never seen it, but I don’t think it is for the faint of heart.

Remember that 70 is the number. What it means, what it represents, how it is derived – who cares? As long the number in the end is at least – 70. Or possibly higher. When success on the PE exam is obtained, then the engineer can then achieve the life-long ambition of seeing one’s own name immortalized on a rubber stamp.

To an engineer, the closest thing to a perfect number is 70. Even if it doesn’t mean 70 any more.

4

May 1, 2012

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According to a friend of mine, 4 is an important number for engineers. This statement is at first strange since my friend, we will call him “Wade”, is not an engineer. How can he know?

But according to “Wade”, one can have a flock of birds, a gaggle of geese, a herd of elephants, a school of fish, but when it comes to engineers:

The set E of a number n of engineers, when gathered together and n is greater than or equal to 4, will create a “Yawning” of engineers.

{E: n>=4} = Yawning

Something tells me “Wade” is making fun of engineers, but I’m still working on that.

1000

April 24, 2012

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All right, it’s soap box time. Somebody’s got to do it.

The number 1,000 is GREAT. It is the answer to many simple measurement questions:

How many meters are in a kilometer? How many grams in a kilogram? How many milliliters in a liter?

There are a lot of numbers that engineers like, and though they may not have this one as their favorite, engineers like it when all you have to do is move a decimal to change units. This definitely beats 5,280 or 16 or 8 or other odd numbers* one would have to memorize in a different measurement system other than the metric system. Regardless of Democrat or Republican, if a candidate had as his or her main platform to convert to the metric system, I know who I’d be voting for. Especially if they also made science fiction the national movie genre.

*Yes, all the odd numbers used as examples are actually even numbers, but that just shows (in my mind) how strange the system we have is.

2

April 17, 2012

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This week at engineeringdaze, we are going to follow the exploits of the first engineer, the caveman named Tork. Tork was so advanced for his era, being an engineer, that he was frequently shunned by other cavemen. But that is another story. Today, we look at a number that was important to Tork.

Tork wanted desperately to  have a cave-dwelling relationship with a cavewoman. The number 2 was high in his engineering caveman mind. “If there is me, and there is her, there is 2 of us.” Though an engineer, he was still a caveman and did not have lofty thoughts. Some may think these thoughts are not much different than most any man, caveman or otherwise. But for Tork, who lived in a time when numbers were not used that much, the number 2 was special. He, being an engineer, understood that 2 meant more than him. He understood that 2 meant he had to impress the cavewoman. He understood that 2 meant possibly devising equations in order to calculate his chances with the cavewoman. Indeed, 2 was a very important number to him.

Unfortunately, Tork suffered the same difficulties that all engineers that followed him would suffer. Tork used 2 small sticks to draw in the dirt at times, and figure things out. He carried them with him in a small pouch he fashioned in his caveman “shirt”, and he held them in place with a piece of bark. Thus, he cursed all engineers throughout history by first “inventing” the pocket protector, and then being seen as too much of a geek by most cavewomen, who were attracted to the cavemen whose arms were stronger due to having to pick up big rocks instead of calculating how to live without having to do that.

Meanwhile, Tork was still hoping for: 2.

62.4

April 10, 2012

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Understanding that engineers have to adapt to this English-unit culture, the engineer keeps important numbers in mind, or at least nearby. 62.4 is one of those numbers.

62.4 is the number of pounds in one cubic foot of water, or its density. The engineers will point out that this density, of course, is dependent on the atmospheric pressure and the temperature of the water. The density of water at standard atmospheric pressure drops to 62.00 pounds per cubic foot of water at 100 degrees F, and down to right around 60 when water is about to boil.

The engineer will need this number in many circumstances when dealing with water – strength of structures holding water, pressure at depths, storage of water, and all kinds of neat applications.

If you are a non-engineer and you are, say, driving by a dam that is releasing water at a rate of X cfm (cubic feet per minute), you can then know how much that water weighs. And then, your life will be just a little more fulfilled.

Trust me, I am an engineer.

9.81

March 27, 2012

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Some may consider this a strange number to be of importance or meaning to engineers. Some, but not engineers. The engineer knows this number, 9.81, is one to be remembered and, if it didn’t sound too emotional, cherished. Many non-engineers out there may remember what this number represents from their science class in high school.

9.81, combined with the units of meters per seconds squared is the acceleration due to gravity, at the earth’s surface. It shows up in many equations, especially in mechanical engineering, and is represented by the constant “g”. Thus, astronauts and fighter pilots experience g-forces, or forces as if many times the force of gravity. This acceleration due to gravity means that an object falling near the earth’s surface, discounting air resistance, will travel 9.81 meters per second faster for every second of falling. I know, fascinating.

Sure, we could also talk about 32.2, the English equivalent of “g”, with the units of feet per seconds squared, but let’s not ruin the engineer’s enjoyment of this constant by bringing in a sub-standard unit of measurement. (Thanks.)

3. 14159265358979323846264338…

March 20, 2012

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Yes, pi, an important concept to mathematicians, is also a great number for engineers. Engineers don’t get all emotional, or verklempt, or sensitive about pi, like mathematicians do. Mathematicians can be so emotional – at least when compared to engineers. Mathematicians even celebrate pi day, March 14, or 3.14, as a tribute to pi, and as an excuse to eat pie. Trust me. I know this for a fact. I have a brother who, along with his wife, are both math professors and they have a pi day party every year.

But, whereas mathematicians get so very emotional about this concept pi, engineers simply use the number. It shows up in many places – tucked into equations, sprouting out of various engineering applications, and materializing in all sorts of engineering phenomenon. Mathematicians can talk about the theory of pi, like, “Is there an end to it?” But engineers simply use the number for improving our way of life.

Let the math nerds have their pie. Engineers, the cool ones, will continue to use pi and numbers like it to serve society in their everyday lives, superheroes in disguise.

3600

March 13, 2012

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What is so interesting to an engineer about 3600? Well, here’s the explanation. When an engineer goes on a trip, especially with the family, he does not want to be listening to what his kids call music, or what his wife calls conversation. Not when a road trip presents so many wonderful opportunities for calculations to be done – What mpg is the car getting? What is our average speed, even considering stops? What is our ETA?

3600 starts them all. The first thing to do is check to see if the speedometer is giving us the proper reading. Assuming you are on an interstate, lock in the cruise control, then measure the seconds between mile markers. And, here is the tricky part, divide that number of seconds into 3600. This yields the mph you are going. Then compare this to the speedometer. You can try this for different speeds – 60, 65, 70, etc. If there are differences, the family can discuss whether this is because the speedometer is actually off, or if the tires may be under-inflated, or other reasons.

So, put away the Disney DVDs, get out a stopwatch and calculator (or use your smart phone), and really enjoy the drive.

Use the number 3600. The engineer in the family will appreciate it.

(For a whole lot of fun, convert it to metric!)

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