Part 27 - Steam

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'Ah, Lee,' Principal Ball bounced down the corridor. 'Glad I found you. Could you possibly fill in for Anna McTavish? I'm sorry about the short notice.'

'Not right now,' Dr Zhang said. 'I'm sorry, Melvin. I have to maintain my genius status and there's a spatial location algorithm, with a few bugs, waiting for me. How about Denny? I am sure he can drag himself away from his Soduku puzzle.'

Denny looked at him cynically. 'If you don't do some teaching soon, you'll risk blowing your cover story, never mind your blooming tax exempt status.'

Principal Ball beamed at Denny as Dr Zhang slipped away. 'The class is in room 114.   Anna was planning to talk about sound but you can explain steam engines to them.' 

I followed as they marched rapidly down the corridor to our classroom, wondering why a teacher would need a cover story. Denny ducked into the cleaner's room and reappeared with a bucket and a bicycle pump as Principal Ball walked away. I slipped into the classroom behind him. 

He checked the class list. 'Now I just marked last week's homework,' he added with an ominous pause. 'And, I was pleasantly surprised at the number of inventions you were able to list. Everyone got the wheel and fire but everybody - except Ryan - missed the piston pump.' 

Ryan, a thin, sandy-haired youth, bounced to his feet waving his arms triumphantly. 'Thank you. Thank you,' he said in response to the sardonic cheers. Licia grabbed his shirt tail and pulled him down to his desk.

'So, today, I want to tell you a story,' Denny said as the applause died away.  'It is about a few men who started the Industrial Revolution making almost everyone on the planet rich beyond the dreams of medieval kings.   And this all started with a few men tinkering with a device used to pump water in Roman times.'

'Many of you will have inflated your tires with a bicycle pump similar to this one,' Denny announced as he put the end of a pump into a bucket of water, 'but, just in case you haven't, I brought one you can look at.' Suddenly, everybody ducked under their desk and I was wondering why, until I was soaked by a jet of water as Denny shot the pump at me. 'This is a piston pump,' Denny said with a wide grin. 'Pull and it will suck air or water into the cylinder. Push down and it will force the air or water out.' Denny handed the pump to Ryan who promptly made a vulgar squeak with it. Denny rolled his eyes. 'Please pass it around.' 

'Since Roman times it was used to suck water up from wells but if the well was more than about 33 feet deep, (ten metres for you metric types), it didn't work.' 

'So, in 1644, Galileo asked his student, to solve this problem and Torricelli invented the barometer, demonstrating that the weight of the earth's atmosphere was holding up the weight of his column of mercury and thus limiting the lift of a suction pump to a maximum of 76 cm of mercury, equivalent to about 33 feet of water.' 

At the back of the class, students were competing to see who could make the most vulgar hissing, gurgling, squealing or slurping noises with the bicycle pump. Denny ignored them. 

'Otto von Guernicke attached two hemispheres together and created a vacuum by filling them with steam and cooling them until the steam condensed. Then he found that two teams of horses were not strong enough to pull them apart.' Denny was writing on the blackboard and he didn't even look around when he was interrupted by a particularly vulgar belching noise just as a jet of cold liquid smacked into the back of my head. Denny looked around at Boz. 'Clif Boswell, if you don't pass that blooming pump to someone else, I will connect it to an orifice of your choice and inflate your ego.'

I blotted the back of my head with a tissue but I could feel the sticky liquid trickling down the back of my neck. It smelled like cola. I decided not to make a fuss about it. I would get back at Boz later, somehow.

Denny continued. 'In 1675, Denis Papin boiled water in a small piston pump thus replacing the air with steam and, as it cooled, the steam condensed back to water and the vacuum sucked the piston closed while lifting a 60 pound weight.'

'Then, in 1712, Thomas Newcomen, an English blacksmith, used this idea to make the first commercially successful steam engine to pump water out of tin and coal mines. He built a large diameter piston pump which he filled with steam from a separate boiler. This piston was connected, by a linkage and a long chain, to a smaller piston pump placed at the bottom of a mine. When the steam was condensed, the large piston was pulled down and this pulled the smaller water pump piston up, forcing the water through a check valve.' 

'Notice that the engine depended on atmospheric pressure but the water pump did not. It was a force pump capable of lifting water hundreds of feet from the bottom of the mine.'

'In 1774, James Watt greatly improved the efficiency by adding a separate steam condenser to existing engines. He also built steam engines using steam under pressure but first he had to improve the machines used to make more accurate cylinders. '

'For the first time in history people had a source of power other than windmills, human muscles, horses and watermills.' 

'Watt and other engineers continuously improved steam engines using them to power railway engines, steam ships and most industrial processes. The mining, iron and steel making and the spinning and weaving industries were revolutionized, creating the greatest increase in productivity and wealth the world had ever seen.'

'By the end of the 1800's, the pinnacle of British steam engineering was the incredible triple expansion engine used by steam ships until steam turbines and diesel engines were developed.'

'We still use steam turbines to generate electricity at every coal, oil or gas fired power station and even nuclear power stations. The gas turbines that drive most aircraft are direct descendants of steam turbines.'

Denny flipped through a copy of our science work book on Professor McTavish's table. 'Now, I have a little work to catch up on, so I think you should read chapter eleven or look it up on the computers. And don't forget to answer all of the questions on page 112.'

I flipped though the pages of the work book and switched on my computer. It took me a few minutes discover that the most famous steam ship in history was powered by three huge steam engines. When it was launched in early 1912, the Titanic was the most luxurious passenger ship in the world. On her first voyage across the north Atlantic, she hit an iceberg and sank. I spent the rest of the period skipping through the web sites on Titanic history, photographs, deck plans, engines etc. at http://www.titanicandco.com/titanic.html. I was fascinated by the incredible series of events that contributed to the disaster.

Meanwhile, Denny was scribbling complicated formulae on the chalkboard and most of the students were doing something else. Some were gossiping in whispers, Licia was drawing elves and Miguel seemed to be copying down Denny's blackboard work. 

When the bell rang at last, most of the class stampeded from the room while Denny had covered the chalkboard with equations that included most of the Greek alphabet.


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