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Answering ‘why’ Questions In Science: A Common Mistake And How To Avoid It.

A quick overview of a common mistake

Date : 14/08/2018

Author Information

Luke

Uploaded by : Luke
Uploaded on : 14/08/2018
Subject : Physics

In my experience, teaching at university s as well as at other levels, one of the main ways many people lose marks when taking science exams is not answering the question which has been asked. A prime example of this is the why question.


Take for example the following:

Isotopes of carbon have the same chemical properties, explain why?

When first given this question many students respond with answers such as, because they react in the same way or reactions have the same outcome and while these answers are technically correct, they do not answer the question. But as I am often asked, why are they wrong?

Let us look at the parts of the question in more detail, a technique I favour is to break the question into its component parts, so & we have the Who (isotopes of carbon), we have the What (Chemical properties) and we need the Why . So for this question we need to understand what an isotope of carbon is (an atom with 6 protons but a differing number of neutrons), what chemical properties are (how they react with other chemicals), and the knowledge to link them together.

We can clearly see now why an answer of they react in the same way would be wrong: this is just rewording the information in the question back to the examiners. To answer a Why question, you must link the Who with the What , and most answer should therefore contain a descri ption of what the Who is: Isotopes of carbon have the same number of protons and electrons (in the same configuration).

We then need to tie this descri ption to the What : It is the Number of electrons (the configuration of the electron orbitals) which governs the chemical properties of a molecule. Combining these two parts together gives the answer: They have the same number of proton and hence have the same number of electrons in the same configuration. It is the electron configuration which governs the chemical properties.



This resource was uploaded by: Luke