would be fine if it were downhill all the way to school and then downhill all the way back home too bad the world just isn't made that way all your life long you'll be digging in and making your muscles work for you but you and joe and jimmy are lucky you're living in a very special time in the world's history a time when other kinds of power help you to get to school or do the other things that need to be done long years ago all the work of the world was done with this power alone with human muscles indians used the power of their muscles to grind corn every job was done by muscle power whether skinning a buffalo or boring a hole in  years went by and people learned to use animal muscle to work for them but the work was slow and heavy they look for other kinds of power to help them then people found how to use the power of the wind it's much easier to let the wind push than to carry a heavy load with muscles the power of the wind will work for us on the lam too the only work that this windmill is doing is to wear a little skin off jimmy's finger but a windmill will run a machine that pumps water or does other useful work another kind of power that people discovered long long ago is water power water flowing in rivers can carry boats and heavy logs and rafts water power will turn wheels too little wheels for fun or big wheel when men first settled in our land they built water wheels in the streams on the banks they built their mills and factories the power of the water turned the machine today we build our factories fire from the river and yet the power of a river may be the power that runs the factory the power comes along the pathway of electric wires lets see how we can use the power of flowing water to do work for us in a factory many miles away first we make the water turn a water where this wheel turns a machine called an electric generator the electric generator turns electricity flows from it flows through wires to the factory far away here inside our factory is a real electric motor tiny but real if we attach wires from the generator electricity makes the motor turn and when the motor turns it will run machines that work for you know how electricity can make something turn let's find out by building a real electric motor of our own as joan doesn't happen to have a flowing brook and a water wheel and a generator in her room she can use electricity from a battery joan has wrapped a wire around a nail when she connects the two ends of the wire to the battery electricity flows through the wire something strange happens watch a magnet the wire and nail together are called an electromagnet you can make an electric motor with a electro magnet like this here is a cardboard box top balanced so it will turn easily the electromagnet pulls the nearest paper clip when jones stops the electricity as one clip goes by and then starts it again it will pull the next clip full stop full stop stop simple isn't it and yet a real electric motor works in almost the same way in your home the power from an electric motor pushes air on a hot day and washes your blue jeans and tells you that you're going to be late for school if you don't hurry but don't forget that the electric power that here is another useful kind of power before you were born the power of steam and old locomotives like they pulled the heavy loads across our country whether the engine is a locomotive or a toy steam engine the main parts of the same there is a boiler that holds water and there is a fire that changes the water into steam when the water boils into steam the pressure of the steam makes a wheel turn the power of steam will turn up wheel in another way you can make a steam turban by cutting a piece of aluminum kitchen floor like this a pin stuck in a pencil eraser will hold steam turbines are used to turn the profilers in a huge ship imagine how much power it must take to turn this and in many places the electricity that turns the motors in our factories comes from the power of steam you can see how steam power will turn a generator just as water power turns a generator when the generator turns electricity flows from it it flows through wires to turn the motors in our factories and light our city another useful kind of power is the power that comes when something burns even the flame of a match has a great deal of pushing it here is an experiment that shows the power of fire first we'll put two matches in a small bottle if you do this experiment wet the stopper and put it in the bottle loosely we'll light the matches with a magnifying glass watch when the matches light hot gases push out the stop it's not hard to see how the power of hot gases can be used to turn to you however instead of matches you're a good deal more likely to find engines that burn gasoline it's the power from burning gasoline that makes an automobile go hot gases from burning the oil make the wheels of a diesel truck go around hot gases push jet planes and rockets through the air the gases shoot out through a tube in this model plane just in years to come when the sun goes down the electricity that lights our cities may come from another kind of power the power of the atom you and i can't experiment with atomic but you can find out about other kinds of power you can move cargoes with the power of the wind you can do work with the power of falling water you can use electric current to turn a whe you can turn another wheel with the power of steam you can even make a car popping machine with the power of burning gases and jimmy will always go on using muscle power but you're the fortunate one you're living in a time when you have other power to do most of the heavy work that muscles used to do