Monday, June 3, 2013

June 3rd, 2013

Fresh Air Matters... with Capt. Yaw

OK, I give up. I really do. I thought that school was supposed to teach people things – not get them to pass exams and then forget all about what they were supposed to have learned.

Almost daily I meet supposedly educated people, those who went to school, and in many cases universities, who are unable to write, calculate or even be in possession of basic general knowledge useable at employment level. All the certificates and diplomas in the world are nothing more than toilet paper, if the knowledge that was supposed to be learned is not retained. Sadly, the pre-occupation with ‘passing an exam’ has become so great that ‘learning and retaining the knowledge’ has become a thing of the past

I have lectured at colleges and universities and been an examiner. I am not an outsider to the system. Educational systems like ‘passes’ and ‘exam scores’ as a measure of success. It is a flawed system.

For day-to-day working, the person must be able to remember subject matter beyond passing qualifications. Passing your driving licence, because on that particular day of the test you remember the rules of the road, is not good enough – you need to remember them EVERY day. If you don’t, you should have your driving licence taken away from you. The same should happen with degrees, exam results and, of course, pilots licences.

For example, imagine you had to look up your name every time somebody asked you – you would feel silly, I hope! Your name is a necessary part of your daily interactions. Likewise, you remember that there are 100 pesewas in a Cedi (I hope!). However, I have recently come across far too many people who cannot give me a snappy, correct or even reasonable answer to even half of the following questions…

Q1. How many metres are there in a kilometre?

A1. Kilo means ‘thousand’, so one kilometre is the same as one thousand metres.

Q2. How many grams are there in a kilogramme?

A2. For the same logic, there are one thousand grams in one kilogramme.

Q3. How many millimetres are there in a metre?

A3. Milli means a ‘thousandth’, therefore there are one thousand millimetres in one metre. (a millimetre is ‘one thousandth of a metre’). (it scares me how few people seem to know this)

Q4. How many milligrams are there in a gram?

A4. By the same logic there are one thousand milligrams in one gram.

Q5. How many litres are there in a cubic meter?

A5. This catches some people out, but it is actually how the definition of the litre is derived. One metre cubed contains one thousand litres. Some people do not appear to know what a ‘metre cubed’ is – it is a volume ‘one metre by one metre by one metre. To expand that, one metre cube of water weighs one tonne, and one litre of water weighs one kilogramme. For the record, one cubic metre of air, under reference conditions, weighs 1.225kg – making water roughly eight hundred times heavier than air.

Q6. How many millilitres are there in a litre?

A6. Using the logic of Q3, there are one thousand millilitres in one litre.

Q7. How many degrees are there in a circle?

A7. This is important knowledge for navigation, manufacturing, construction, etc. The number is 360. But why? Well, time and circular measure are connected. Both were the development of the Babylonians – and they loved the number 60. That is why your clock has 60 minutes in the hour and 60 seconds in the minute – and if you look at an analogue clock, you can quickly see that the hands of the clock always work around in degrees of movement. For Geometric and Navigational purposes, the division of the clock face was not accurate enough, they needed to increase the resolution, so they developed the degree, 360 degrees in one circle. Now, in order to get 360 degrees, simply imagine that you superimpose a hexagon onto the surface of the clock, and then divide each face by 60 units (I know they were funky people with their love of 60), and then you have 360 degrees in a circle. The protractor is a great device for visualising this, but few people understand it.

Q8. How many minutes are there in a degree?

A8. Each degree is divided into 60 equal parts, each one being called a minute (the same as the Babylonians divided each hour into 60 minutes, it was their standard way of dividing things).

Q9. How many seconds are there in a minute?

A9. Yup, each minute of a degree is divided into 60 seconds, for the same reasons.

Q10. What is Pi?

A10. Pi is the CONSTANT relationship between the diameter (a straight line crossing through the middle of) any given circle and its circumference (the distance around the edge of the circle, which for any other shape edge is called the perimeter). If you put a piece of string around a circle, and cut it to length, then cut a piece of string the length of the diameter, and you calculate how many times the diameter will divide into circumference you will ALWAYS get Pi. Which is roughly 3.14159 or can be approximated at 22/7. Without knowing (and understanding) Pi you cannot compute important areas and volumes which include circles, spheres, or parts thereof, let alone use radians!

Q11. What is the formula for calculating the area of circle?

A11. Pi multiplied by the radius multiplied by the radius. (in other words Pi.r2) – if you consider the area of a square is ‘the length of one side multiplied by itself’ (L2 ), you can see the use of the squaring of the radius, and then knowing that Pi is related to the overall ratio of the circle, it suddenly makes sense. Yet, it is rare to find a person coming from any level of education with this BASIC understanding of something we use every day in our work.

Q12. How many cc are there in one litre?

A12. First if all what is a cc? Most people have heard of a car engine being ‘1500cc’ or an injection of ‘5cc’. But they rarely know that cc means cubic centimetre. That is the volume of one centimetre by one centimetre by one centimetre. Or, since engineers do not use centimetres, they use millimetres; 10 mm2, which is 1000mm3. This is not very big, believe it or not. If you have a one litre bottle of water on your table, it contains ONE THOUSAND cubic centimetres – or ONE THOUSAND millilitres or 1,000,000mm3 of water. So, let us assume that the bottle is circular, has a base diameter of 80mm (or radius of 40mm), therefore, in order to calculate its height (assuming it is a perfect cylinder) we can use the formula for volume of a cylinder which is Pi x radius2 x height.

So, 1,000,000 = 3.14159 x 40 x 40 x H

Therefore 1,000,000 = 5,026.544 x H

Which rearranges to 1,000,000 / 5,026.544 = H

Resulting in H being 198.9438469mm, or in other words, your bottle of water is roughly 200mm or 20cm tall. Furthermore, it contains approximately one kilogramme of water.

Knowing these FACTS is essential in manufacturing, mixing concrete, using wood, steel, or planning resources. It is time that education became about being able to use knowledge to do things NOT than just pass exams and collect useless bits of paper.

Capt. Yaw is Chief Flying Instructor and Chief Engineer at WAASPS, and lead Pilot with Medicine on the Move, Humanitarian Aviation Logistics ( e-mail )

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