Editorial

To understand the students' mind-set, one has to think like a student. That is why every teacher is first a student and then a teacher.

In one of the top research establishments in India, it is the periodic interviews that motivated the scientists to take interest in general things also apart from their specialities. Weekly seminars also keep one abreast.

Questions asked in interviews range from the difficult ones to  test their speciality to simple ones which will probe their mind Let us take a sampling. What is Avogadro's number? What is sin? What is the mass of the photon? etc.

The same questions are asked by the students. How does one make the student understand this mysterious number of atoms in one mole of any substance?

One has to start with simple examples, if a match stick, weighs 40 mg, what is the number of matches in 4 g? If each one weighs 50 mg. what is the number in 3 g? If each one weighs 1.661 x 10^-24  g, what is the number in I g? This 1.661 x 10^-24 g is the atomic mass unit, amu. If ¹²C atom weighs 12 amu '12 g, ... voila. You have the Avogadro number, if the aton... weight had been 12 + Δ m , then one has to take (12 + Δ    m) g for a mole.

Then wiry do we lake the carbon 12? Why is it that the atom.. mass is a whole number! One discusses isotopes, binding energy and so on and finally other atoms taken earlier as standards and why carbon 12 is taken now.

What are the hidden assumptions? Similar particles have the same mass? Do similar atoms have the same mass. Why?

No level is difficult for the students. Only they have to be told from their level.

There is no substitute for discussions and interactions with he students. No standard has to be diluted but any topic can be simplified.

The biggest hurdle for advancement of science is to quote "thus speaketh the text-book". We have to teach the students to think for themselves. Every student has to think, meditate, realise what is learnt and apply.