Symmetry is one of the easiest topics to teach. The idea of line symmetry is probably innate and is cultivated from an early age. What parent
does not have proudly displayed their 4 or 5 year old's first attempt at combing
art and maths; paint splashed on a piece of paper and folded over to produce a
glorious symmetrical design. How many homes throughout the world have these
masterpieces attached to fridges or other suitable surfaces?
As a young teacher I thought I had delivered the perfect lesson on scale drawing. I set the appropriate exercise and expected the pupils to enthusiastically tackle the tasks, applying their new found knowledge. What could go wrong? The folly of youth. Immediately a hand went up asking for help. 'What's the problem?' I enquired. 'You can't do this one' said the indignant pupil. The question involved working out the actual length a real car given the length of a toy car and the scale to which it was built. 'Why not?' I asked rather bemused. 'They haven't even told you what make of car it is. how can you possibly do it?' So much for the perfect lesson.
This is really simple lesson on estimation that makes the topic REAL! It is easy to do and works, plus it allows you to escape the confines of the classroom. I guess we have all heard the song 'The wall' by Pink Floyd. I enjoyed
listening to it but was never quite sure about the lyrics. At this time of year
I think most teachers would prefer to listen to Alice Cooper, you know the song
'Schools Out'. Just to remind you about Pink Floyd’s lyric
Irritated by paper aeroplanes being thrown in your
classroom? It happens to all of us during out teaching career at one time or
another, some ‘character’, usually a boy, has learnt how to make a paper
aeroplane and uses your class to demonstrate his new found skill. I am always
amazed at the poor level of construction of these missiles; they are usually
just successive folds along a central axis, a demonstration of symmetry. My dad
taught me a far more intricate and aesthetically pleasing method but I’m not
sure if it flew as far as the, in my opinion, inferior models.
What is a decimal? Can you answer in one sentence? If there
was a pause for thought good, because it is a really difficult question to
answer, we are so used to decimals we forget what they are. If you did struggle
imagine pupils’ confusion when you start to talk about decimal fractions or
changing fractions into decimals.
We have all at one time or another thought ‘decimals should
be easy to understand’. After all no matter where we are in the world money is
based upon the decimal system, which child has not experienced that? Yet if you
ask a student what is the value of 7 in 0.12379 the answers given will probably
be not what you want.