*be sceptical - take nothing for granted!
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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.

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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. 

 

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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).

 

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*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).

 

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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

The Secret

The Secret

By Richard McKie

 

 Download PDF (for e-readers)

 

Lansing Michigan was a fine place to grow up, she guessed.  It was nice, and safe.

Her dad worked in the Michigan State Government and her mum stayed home. They weren’t rich but they were comfortable. Their new house was big, the nicest they had lived in and it was in a really good area. 

She had never been overseas, unless you count nearby Canada, and that was mainly on trips to Niagara Falls, usually when one of Mum’s sisters came to stay. When they passed through Sarnia, into Canada, Dad would always say "Yea! Overseas again!". It was about his only joke.

Sometimes they went through Detroit. But after what had happened there the last time she shut that out of her consciousness. No wonder she is timid and takes fright easily. Now if a friend even seemed to be driving in that direction she would go into the foetal position and shut-down.

Read more ...

Opinions and Philosophy

Losing my religion

 

 

 

 

In order to be elected every President of the United States must be a Christian.  Yet the present incumbent matches his predecessor in the ambiguities around his faith.  According to The Holloverse, President Trump is reported to have been:  'a Catholic, a member of the Dutch Reformed Church, a Presbyterian and he married his third wife in an Episcopalian church.' 

He is quoted as saying: "I’ve had a good relationship with the church over the years. I think religion is a wonderful thing. I think my religion is a wonderful religion..."

And whatever it is, it's the greatest.

Not like those Muslims: "There‘s a lot of hatred there that’s someplace. Now I don‘t know if that’s from the Koran. I don‘t know if that’s from someplace else but there‘s tremendous hatred out there that I’ve never seen anything like it."

And, as we've been told repeatedly during the recent campaign, both of President Obama's fathers were, at least nominally, Muslim. Is he a real Christian?  He's done a bit of church hopping himself.

In 2009 one time United States President Jimmy Carter went out on a limb in an article titled: 'Losing my religion for equality' explaining why he had severed his ties with the Southern Baptist Convention after six decades, incensed by fundamentalist Christian teaching on the role of women in society

I had not seen this article at the time but it recently reappeared on Facebook and a friend sent me this link: Losing my religion for equality...

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