Bioequivalence and Bioavailability Forum

Dear all,

I want to share with you a little story told by one of my friends, professor of chemical engineering. In a decisive examinination for a group of students (between grades 4 and 5, where 1 is best and 5 worst) amongst others they were free to select from two excercises.

1. Dealing with the chloralkali process. They had a similar exercise in a previous exam, and the topic was exhaustively covered in their tuition. But: It’s a tricky task; you have to set up the chemical equations, get the stoichiometric conversion of masses and volumes to moles right, and solve a system of a quadratic equations. Twenty minutes of work minimum and a lot of space for mistakes.
   
2. The other one needed some creativity. You have a pipe and open it to superheated steam. Given:

   l₀ = 1.5 m
   ∆_T = 250 ℃
   linear thermal expansion coefficient α = 0.00012 in/(ft·℃)
   ∆_l = l₀·α·∆_T
   1 ft = 12 in

   What’s the change in length?
   Obviously 1 in = 1/12 ft, 0.00012 in/(12 in·℃) = 0.00001/℃ and therefore, ∆_l = 1.5 m × 250 ℃ × 0.00001/℃ = 1.5 m × 2.5 × 0.001 = 0.00375 m or 3.75 mm. Took me five seconds to come up with the answer…

All of his students chose the first exercise and struggled with its pitfalls.

My friend was somewhat frustrated about nobody selecting the second one. The next week he presented it in a noncompetitive way to his students with a grade 1 or 2 only. He stated that the outcome wouldn’t influ­ence their grade – it was just to satisfy his curiosity. All of his students succeeded, but also

• all of them needed a pocket calculator,
  
• all of them made at least (!) one unit conversion, and
  
• nobody recognized the possible shortening of the fraction.

What’s up with the students? Is this an Austrian specificity – or are we just getting old?