Relativity

With my ten year old being taught about global warming at school along with its effects, our homework discussion turned to the causes being a matter of opinion. This lead into the topic of relativity and how one person’s perception might vary from another’s depending where they were coming from. In practical terms during the last century, through the 60s Chinese people in China believed Chairman Mao and his policies even though this led to millions of their deaths. At the same time the West considered him a nut case: matter of perspective.

Anyway as you do with a ten year old, this got into the Theory of Relativity and Einstein and as ten year olds do, a demand for an explanation beyond my reference to the Cultural Revolution.

To explain relativity, I used the old train travelling image. 

We have X on the train moving along. Three people A, B and C stand along the platform looking at X.

                                                      X      ----->

A______________________B_____________________C    

At this time B is closer to X so may see X immediately at speed of light. A however is further away and so A will see X later than B would see X and in fact by the time the light had moved back to A X would have moved further away. C is also further away than B so would see X after B but since X is moving towards C the image would be seen sooner – but eventually C would see X before B, and certainly before A.

Of course in a more complex form you can have obstacles in the way like houses or trees and the train could be turning corners but the principle is the same.

Reverting back to lectures on Global Warming, I pointed out that there were many factors and over many centuries the earth’s temperature has always been changing but slowly. The question was really whether man on earth was contributing to this warming and if so what could be done about it?

We know that the Amazon rain forests are being cut down and millions of trees are no longer soaking up carbon dioxide in the air which is a bad thing.  In 1958 Chairman Mao had ruled that everyone should make steel so all available trees were cut down all over China to stoke the furnaces and so there was no harvest and millions starved. Bad thing. And large parts of not just China but other places such as India have had their trees cut down for fuel. Having covered most of China some parts from the air still look like a moonscape. And don’t start me on billboards in the USA.

So back to relativity and what can Australia do about it? Around 1,400,000,000 people in China. Nearly a billion in India. In Australia around 24,000,000. So yes pollution is bad but the big polluters have to take a lead in cleaning up their act and for people to teach and preach in Australia that our country is going to make China, India or even the USA clean up their acts by levying Australians with a tax is a bit like a tail trying to wag a dog. If you are a coal miner you want to sell coal so you will look at the question from that perspective. Someone with a job to push global warming theories will have another. Yes we need to clean up the planet but it needs working together and communal thinking like when the train has stopped and we are looking at it all from the same spot.

My daughter said she understood but really wanted to know what the rating stamp meant on the plastic bags…