How Power Drives Machines (1963)

[Music] one morning Bill and his father had planned to clean their attic but in an old trunk they had found a book a diary it had been written by Bill's great-grandfather when he was a boy in the 1850s the sound of a passing jet reminded them that they still had a job to do in the world of today but the jet also reminded bill and his father of something else of one big difference between the past and the present that was power the power we Ed to drive machines Bill knew that the many ways we use power today were not all known back in the 1850s back then in Pioneer American communities most of the work was done by muscle power people depended on the power from their own muscles or from the muscles of animals for doing work but vels were not the only source of power the power of the wind that blew sailing ships across the sea was also put to work to turn windmills which sometimes operated machinery for grinding [Applause] grain but most windmills used the power of the wind to pump water from Wells the power of moving water was also used to do work moving water was used to turn water wheel Wheels the Turning water wheels drove other wheels these wheels operated machines which ground grain or did other work for the people of the 1850s people had used water wheels for many years but water in another form was coming into common use in the 1850s water in the form of steam in the world of Bill's great-grandfather steam first became important as a source of power to drive machines it was used to drive steam locomotives and to turn the paddle wheels of [Applause] Steamboats now in the world of the 20th century Bill's father showed him how steam is used in Steam Engines heat changes water to steam and there is enough energy in Steam to move the lid of a pot now it was easy for Bill to see how steam could be used as a source of power to drive machines in a steam engine there is a cylinder and a piston the Piston moves up and down in the cylinder just as Steam inside a pot can move a lid steam inside a cylinder can move a piston the moving piston can be made to move other things it can be connected so that it turns a wheel and the wheel can be used to move a train or to move a boat and so in this way in steamboats and trains steam was used as a source of power in the 1850s to drive machines by moving a piston in a cylinder steam is not as important as it used to be for moving Pistons today in most machines the movement of Pistons depends on another source of energy in an automobile for example gasoline is burned in the cylinders of the engine to move the Pistons to show how burning gasoline drives a car Bill's father covered the large end of a funnel with aluminum foil and put it on the stove he dropped some pches into the funnel and then put a piece of foil on the narrow end now the funnel was something like a cylinder closed at both ends then he lit the burner when the air in the funnel gets hot enough the matches ignite and produce hot rapidly expanding gases that push the cap off the funnel in the cylinders of an automobile engine expanding gases from burning gasoline push the Pistons and they move up and down the moving Pistons turn a crankshaft the crankshaft carries power to the wheels to drive the automobile while nearly all automobiles use gasoline for their fuel many trucks and other large machines burn a kind of oil in their engines this oil is called diesel oil because it is used in diesel engines expanding gases from burning fuel supply the power to drive this truck and many other machines that carry us and do work for us fuel is used in a different way in jet [Music] engines to show how burning fuel supplies the power to drive a jet Bill's father wrapped some foil to tightly around the head of a paper match and put it on a launcher made from a bent paper clip then he used another match to ignite the one on the launcher when that match ignites hot gases will rush out from under the foil and move rapidly to the rear watch as this rapid movement of the gases to the rear makes the mat shoot forward just like a jet in a jet engine air comes in at the front fuel is burned inside the engine then hot expanding gases rush out the rear this rushing of the gases to the rear makes the Jets move forward and the jet engines move the airplane expanding gases that rush to the rear also Supply the power to drive Rockets power from expanding gases can be used in still another way in this turbo prop engine hot gases from fuel burned inside the engine push against a wheel called a turbine the turbine turns the propeller a turbo prop engine is one type of gas turbine engine this little propeller is turned by steam blowing against a turbine that is connected to the propeller the steam to operate this steam turbine comes from water boiling in a can on Bill's stove in this water turbine model water flows through a tube to the turbine the power of the moving water will turn the turbine a turbine wheel isn't very different from a water wheel but it turns much faster bill could see that this spinning turbine is connected to a small electric generator the turbine operates the generator which produces enough electricity to light the little bulb at the top in the same way that water is used in this little turbine to produce electricity water is used at Great dams and waterfalls to spin large large turbines in powerhouses while moving water is important for generating electricity steam is also used just as Steam turned the Little Wheel on Bill's stove Steam and large power plants turns great turbines to generate electricity the turbines are turned even faster than water could turn them Bill's father reminded him that we depend on electric power to drive many kinds of machines in our homes machines such as electric mixers vacuum [Music] cleaners and can openers but electricity can drive more than small machines large ocean ships are also driven by electricity produced by steam turbines in this ship Steam for the turbines is produced by the heat of atomic energy the power to drive most trains comes from electricity produced by diesel engines the power to turn this toy is coming from sunlight this is called a radiometer Bill thought that perhaps in the future sunlight might might be used to power large machines this would add another source of power to the many we have today yes the world of today is quite different from the world of Bill's great-grandfather and yet it's likely that when Bill himself is a great-grandfather the world will be even more different because of the power that will drive the machines of the future