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

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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

Malta

 

 

Almost everyone in Australia knows someone who hailed directly from Malta or is the child of Maltese parents. There are about a quarter as many Maltese Australians as there are Maltese Maltese so it is an interesting place to visit; where almost every cab driver or waiter announces that he or she has relatives in Sydney or Melbourne.

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Fiction, Recollections & News

The Craft

 

 A Cloud prequel

 

 

 

Chapter 1 - Caught short

 

 

 

 

Christmas 2069 approaches and in the midst of the greatest retail spending frenzy for decades Bianca has been trying on clothes..  They're at Bergeroff Goodman, an up-market store. Bianca has been brought here by Margery who frequents such expensive places.  Unlike many other retail establishments in the world at this time of year, the store is not over-packed with shoppers.

Elsewhere many customers will expend their entire available credit and have even accumulated credit from earlier in the year to allow for this annual celebratory splurge.  Much of it will be expended on personal services, personal wellbeing, exercise, entertainment and of course religious practice and many will exchange gifts of credit towards these services with friends and loved ones.  But this store is very up-market and discrete.

This Monday lunchtime Margery is encouraging Bianca to buy a top quality black wool and mohair suit with a knee length skirt, similar to the one Margery is wearing.  Bianca had been resisting and equivocating when the call of nature gratuitously cut short their struggle.  The older woman had assumed Bianca's resistance was for financial reasons, insisting that a good suit is not an extravagance but an investment in Bianca's future. 

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Opinions and Philosophy

The Chimera of Clean Coal

The Chimera - also known as carbon capture and storage (CCS) or Carbon Sequestration

 

 


Carbon Sequestration Source: Wikimedia Commons

 

Whenever the prospect of increased carbon consumption is debated someone is sure to hold out the imminent availability of Clean Coal Technology; always just a few years away. 

I have discussed this at length in the article Carbon Sequestration (Carbon Capture and Storage) on this website. 

In that detailed analysis I dismissed CCS as a realistic solution to reducing carbon dioxide emissions for the following reasons:

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