## Tuesday, October 23, 2012

### Dopplers, Bugs, Time and the Eleven Plus

Can one approach of the Eleven Plus be likened to the Doppler Effect? There is a wonderful description of the Doppler Effect in a `ThePhysics Classroom’. The lesson is about a little bug making waves. (No eleven plus child can be called a little bug – and no eleven plus child will ever make waves!) If the bug shakes his or her legs then waves flow out and cause a disturbance. (Who ever thought of an eleven plus child causing a disturbance?)

In many explanations of the Doppler Effect the example is used of the siren of an ambulance approaching. We hear the sound grow closer and closer – then there is the moment that the ambulance passes – with the sound fading. In the eyes of some the Eleven Plus can be likened to the awareness that the examination is approaching – the impact of the actual examination on the family – and then the urgency leaving – only to be stirred up again by the results.

Hindsight, however, is wonderful. We use hindsight to look back and think of what might have been. Suppose, for example, that a question on time stumped your candidate in the examination. You look back to when your little one was three yours old and you were teaching time. Your `self-help’ books on child rearing probably told you that it is difficult for a three year old to recognise that to be orientated in time he or she needs to be able to classify events of the past in terms of what happened first. (Try explaining that to your three year old!)

But parents  persevere, don’t they? They teach today, tomorrow and yesterday. They work on the days of the week, months of the year and then the concept of a year. Almost every parent will use the notion of a birthday or Christmas to explain the passage of time.

It is these little ripples of awareness that the eleven plus child draws on. When a question arises to do with time your child may possible use elements of the Doppler Effect. He or she may recall your happy, excited and motivated voice talking about the passage of time. A shiver will go down your child’s spine as he or she recalls that there are sixty minutes in an hour – and that some calculations will require an hour to be changed to sixty minutes.