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Monday, December 31, 2012

Eleven Plus and von Pirquet

We hear about some very strange eleven plus results over the years. We hear of children who pass unexpectedly – and of children who somehow do not reach the required standard. There can be little doubt that some questions suit some types of brains. Could there be an easy answer?

If we take a reasonably typical eleven plus question, aimed at an eleven plus high-flyer, we can expect a variety of responses. Do you remember attaching cardboard to the spokes of your bicycle so that as the wheel rotates you hear a variety of clicks and `burring’ sounds? Have you ever envied the freedom of the surveyors walking purposefully along pavements? These men and women are not bound by desks – but often have the freedom of the open air.

Back to our eleven plus question:

A sturdy surveyor is pacing out the site of a projected housing estate. A surveyor needs to know the horizontal distance between two points and uses a trundle wheel with a circumference of 50 cm. Each time the wheel turns it clicks. Two clicks equals one metre.

How many centimetres are there in six clicks?

How many clicks will there be in a typical `T’ junction?

This question requires a degree of calculation – but also shows the need for appreciation of the width of a road as well as car and lorry turning circles. How many eleven year olds have these skills? We can see that the centimetres question can be considered a `fair’ question – but what about the `T’ junction element?

Estimating answers to measuring questions can be highly personal. We know, for example, that a new born baby is measured and weighed on a regular basis. Some parents will even have kept these early records. Height, for example, is a linear measurement. Some earnest parents may have followed the course of testing the hypothesis that the relating height to the cube root of weight! Clemens von Pirquet was involved with the distribution of emergency rations after the First World War. He suggested that the cube root of weight could be divided by the sitting height in centimetres. A figure of 100 was considered normal. One below 94 indicated under-nutrition.

The problem was that if the height was measured just one centimetre too much or too little the whole formula was suspect. Please, if you have time, try this with your eleven plus child!

A child with just one mark above the `pass mark’ can pass the eleven plus. A child with one mark below can fail to win a place in a grammar school. Being one centimetre out can change a result – just as the appreciation of a few `clicks’ can alter a child’s future.