Science Lessons

By Elizabeth Leathbridge, Wodonga Albury Towards Climate Health (WATCH)

Who remembers their science teacher closing a fist with thumb out to demonstrate that running a current through wire wrapped around an iron bar would induce a magnetic pole in the bar, which pointed north in the direction of the thumb?

And in reverse– by spinning a magnet fast enough around a copper wire, enough electron movement is induced to generate a spark of electricity?

This primitive engine, called a magneto, is still used to start your lawnmower. 

We humans provide the force to spin the magnet. Every gardener knows from experience that a magneto’s usefulness is limited by the size and weight of the magnet, not to mention an apparent ability to willfully spin in the wrong direction.

Solution – split the magnet into manageable pieces, each wrapped with coils of wire, and you can assemble a generator, which, loosely speaking, produces enough rapidly repeated sparks to form an electrical current.

Engineers still use this machine to make hydro-electricity – by combining a huge generator with a water wheel to make a turbine, then spinning it. 

We can use the energy of water rushing past the turbine, but, to gain enough force, the water must drop from height under pressure, thus we build large dams.

Where there is insufficient height or water flow, we can heat water to boiling point and use the force of the resulting steam, compressed into jets, to spin the turbine.  

To achieve this, most of the world burns brown coal or natural gas, or uses the energy given off by radioactive uranium.

We’ve all heard about the likely cost of continuing high carbon emissions to us and the climate – and we could risk continuing to use existing “boiler” technology – if we were particularly shortsighted.

To maintain our electricity-powered lifestyles and industries we might need to invent a new sustainable method of power generation, be it large or small, for everyone in the world to share.

Personally speaking, electricity is my favorite luxury.  My house is designed around it – for food storage, cooking, cooling, water supply and sewage disposal.

I’d rather not imagine my spoilt suburban self reverting to the 1930s, when household refrigeration was unknown, meat and vegetables were stored in the cellar, and milk was taken daily from the house cow.  Oh, and ask an “oldie” about the summer aroma of “the long-drop”. 

Ask yourself – could I manage my house without electricity?