*be sceptical - take nothing for granted!
Unless otherwise indicated all photos © Richard McKie 2005 - 2019

Who is Online

We have 97 guests and no members online

Article Index

 

 

 

The electrically literate may find this somewhat simplified article redundant; or possibly amusing. They should check out Wikipedia for any gaps in their knowledge.

But I hope this will help those for whom Wikipedia is a bit too complicated and/or detailed.

image010
All cartoons from The New Yorker - 1925 to 2004

 

 

Think of water in a hosepipe

 

Electricity is a means of transporting energy from a source, like the wind, to a device you use to exploit that energy, like your electric toothbrush.

The usual way of explaining electricity is to use the simile of the flow of water in a pipe (a current of water).  We are all familiar with a hose pipe.  Its pressure is analogous to the voltage; and the flow of water is analogous to the current. 

 

image032
The author - almost two - learning about currents and voltage

 

The work that can be done in an hour, for example if you use the jet to spin a bicycle wheel or push leaves along a path, is the pressure (like Volts) times the current (like Amps) for an hour. 

You won’t be able to squirt the water from your hose far if there is no pressure or if there is no water.  You need both.  If the pressure falls the water ceases to flow.

It’s the same with a stream (current) of electricity making its way down a conductor; for example a wire. The electrical force acting on an electrical current provides the power to do work.

Most quantities in modern physics are named after an early natural philosopher or inventor.  If we had let tradition do it, each would probably be related by some strange number, like the number of feet in a mile; or pounds in a ton.  But most new physical values use the decimal system (the rationalised MKS or SI units: meter, kilogram, second).

A Watt is a measure of Power; the instantaneous capacity to do work; named after James Watt. 

Under this system we define one Watt as equal to one Volt (electrical  force) multiplied by one Ampere (current); or Amp for short.  Read More...

Using this simple relationship you can easily calculate that 1000 Watts of power (one kilowatt) can be carried by a current of 4.17 amps at 240 volts (240 x 4.17 = 1000)

But the same power requires only 0.002 amps at 500,000 volts (0.002 x 500,000 = 1000).  So when you turn on an electric kettle or toaster it will draw around 4 amps in your home at 240V but only 0.002 amps in the very high voltage grid to bring it from the generator in the power station.

Power exerted for a period of time is called Energy.  Physicists measure energy in Joules (1 J= 1Watt acting for 1 second).  But to get to a smaller working number electricity companies like to measure energy in kilowatt hours (1 kWh =  3,600 kJ = a thousand Watts acting for the seconds in one hour) 

When your bill comes, you get charged for the Energy, the number of kWh* you used, not Power (kW).

 

image012

 

*Terminology:  1000 Wh = 1 killowatt hour (kWh); 1000 kWh=1 megawatt hour (MWh); 1000 MWh = 1 gigawat hour (GWH), 1000 GWH = 1 terawatt hour (TWh).

 


    Have you read this???     -  this content changes with each opening of a menu item


Travel

Italy

 

 

 

 

A decade ago, in 2005, I was in Venice for my sixtieth birthday.  It was a very pleasant evening involving an excellent restaurant and an operatic recital to follow.  This trip we'd be in Italy a bit earlier as I'd intended to spend my next significant birthday in Berlin.

The trip started out as planned.  A week in London then a flight to Sicily for a few days followed by the overnight boat to Napoli (Naples).  I particularly wanted to visit Pompeii because way back in 1975 my original attempt to see it was thwarted by a series of mishaps, that to avoid distracting from the present tale I won't go into.

Read more ...

Fiction, Recollections & News

More on Technology and Evolution

 

 

 

 

 

I recently read and commented on Dan Brown's latest novel 'Origin' in which the question 'where are we going?' is answered in suggesting an ever greater human symbiosis with technology.  But what if that's not all?

Regular readers will know that I have an artificial heart valve.  Indeed many people have implanted prosthesis, from metal joints or tooth fillings to heart pacemakers and implanted cochlear hearing aides, or just eye glasses or dentures.   Some are kept alive by drugs.  All of these are ways in which our individual survival has become progressively more dependent on technology.  So that should it fail many would suffer.  Indeed some today feel bereft without their mobile phone that now substitutes for skills, like simple mathematics, that people once had to have themselves.  But while we may be increasingly transformed by tools and implants, the underlying genes, conferred by reproduction, remain human.

The possibility of accelerated genetic evolution through technology was brought nearer last week when, on 28 November 2018, a young scientist, He Jiankui, announced, at the Second International Summit on Human Genome Editing in Hong Kong, that he had successfully used the powerful gene-editing tool CRISPR to edit a gene in several children.

Read more ...

Opinions and Philosophy

Energy woes in South Australia

 

 

 

 

South Australia has run aground on the long foreseen wind energy reef - is this a lee shore?

Those of you who have followed my energy commentaries published here over the past six years will know that this situation was the entirely predictable outcome of South Australia pressing on with an unrealistic renewable energy target dependent on wind generated electricity, subsidised by market distorting Large-scale Generation Certificates (LGCs) (previously called RECs in some places on this website - the name was changed after their publication).  

Read more ...

Terms of Use                                           Copyright