We start this chapter still in the world of the scientists--they are looking to understand principles.  What are the rewards for making a scientific discovery?

• maybe you even get a unit or something you have discovered named after you
• you publish it--get credit for it
• you become respected among scientists
• scientists aren't usually as interested in inventing useful things or in getting rich
  
• would you rather be as rich as Bill Gates or win the Nobel Prize?

Who gets the credit?  Traditionally the scientist, not his assistants (even if they were scientists themselves)
Denis Papin

• worked with Robert Boyle and Christian Huygens
• in 1690 published a design for an atmospheric engine--a steam engine that got its power by condensing the steam, like a Newcomen engine--but it wasn't built
  
• he even proposed a high pressure steam engine (the idea that later replaced the atmospheric engine) but the technology wasn't there
• people were even playing with designs for steam turbines

Many scientists and inventors were members of religious minorities because most professions were closed to them

• in England you had to belong to the Church of England in order to be a lawyer or hold a government job, other kinds of protestants, called dissenters, were not allowed to hold such positions or even to go to the best universities
  
• France was Catholic--for a while it tolerated a protestant minority called the Huguenots, but then they were told they would have to convert or leave the country because the king feared they were disloyal
• in England the dissenters also became the leaders of the industrial revolution--after 1700 the new science begins to lead to new technology as well
  

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Now we will move from science to technology

An industrial revolution is a fundamental economic change:

• between 1770 and 1850 the economy of England changed from mostly agricultural to mostly industrial
• why England? for one thing economy more capitalist, maybe because of the religious pattern in England
  
• this was the result not of one key invention but of technological progress in different fields coming together
• its center is the development of factories (which hadn't really existed before this time), but they couldn't have developed without better transportation creating larger markets and better transportation couldn't have existed without the growth of the iron industry, which couldn't have grown without steam engines
• society had a hard time adjusting to the new economic system

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Iron:

• by 1720 most iron in England was imported due to a shortage of charcoal for smelting
• in 1709 Abraham Darby invented a way of smelting iron using coke (processed coal) instead of charcoal
• the iron industry took off after 1760 since iron ore and coal were both very plentiful in England
• the only snag was that water had to be pumped out of the mines (a mine acts like a well and fills with water)
  
• 1779 Iron Bridge ( photo )

  the first iron bridge, Coalbrookedale

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The early practical steam engines are all atmospheric engines

• To understand, do this experiment:
• Take a plastic container, put a little water in it, and put it in the microwave until the water boils
• take it carefully out of the microwave (without burning yourself) and put a lid on it tightly while it is still steaming hot
• let it  cool and you will see that the lid is pulled down (curves downward into the container)
  
• When you put the lid on the container was full of steam
• when it cooled the steam condensed and turned back into water
• the water takes up much less space than the steam, so the lid is pulled down
• an atmospheric steam engine works on the same principle--fill the cylinder with steam and then condense it
• have a piston that moves in the cylinder--when the steam condenses the piston is pulled down
• attach the piston to a water pump so that each time it is pulled down it pulls up the handle of the water pump and pumps water
  

Early Steam Engines:

• The need for steam engines was to pump water out of mines
  
• Thomas Savery built the first workable engine, using an odd design without a cylinder and piston--using the steam directly to pull up the water
  
• Newcomen Engine (about 1712) filled a cylinder with steam and then sprayed in cold water to condense the steam and draw the piston down.  1/2% efficient, but widely used to pump water out of coal mines. 
• some scientific knowledge about atmospheric pressure/vacuum was necessary, but it was a one part of building an engine
  
• Watt Engine (1774) had had a separate condenser, making the engine much more efficient.  The cylinder always stays hot and the steam is condensed in a separate chamber called a condenser which always stays cold.  You don't waste a lot of energy heating and cooling the walls of the cylinder (animation)
• James Watt later added:
  • sun and planet gear converted reciprocating (up and down) motion into rotary motion to power machines
  • automatic control mechanism to keep the engine running at a fairly constant speed
  • double-acting engine made for much smoother power--close the cylinder above the piston and put steam into the top part of the cylinder while condensing steam in the bottom part and then vice versa
  • more efficient engine using a separate condenser
    

  Watt Engine

• high pressure engines developed after 1800,  needed for transportation applications (the Watt engine was too heavy)
•  significance of steam power