The Nature Of Energy (1949)

[Music] in early days man worked mainly with the energy in his body today we use many forms of energy energy which can work for us in a wide variety of ways we're preparing to shoot a motion picture on energy let's see how many ways we are using energy to make the picture we have our lights and the camera the energy of human muscles does the work of moving the camera when the camera is in place another kind of energy electrical energy will do the work of running the camera well there we are just about ready we use sound another form of energy to talk and give instructions and now we'll check the lights lights use electrical energy do they do work do they move objects not exactly but strong light does cause the indicator of this light meter to move so as we'll see light too is a form of energy well all set camera action and here's what the camera sees some metal balls some matter normally at rest energy is required to move these objects muscular energy lifts the metal ball against Gra city as a ball is lifted it gains in potential energy the energy of position as the ball drops the potential becomes kinetic energy the energy of moving objects this kinetic energy can be transferred through the balls so that the ball at the other end is lifted gaining in potential energy think about what's happening here and you may have a better understanding of potential energy and kinetic energy the same principle is used in a pile driver the kinetic energy that drives the pile comes from the position of the hammer potential energy and how is the hammer lifted by the steam engine which gets its energy from the chemical energy of coal chemical energy can do work when it causes certain sub substances to react with one another for example vinegar and baking soda contain chemical energy this is stored or potential energy when the two chemicals are kept apart but mix them together and you see a transformation of a little of the chemical energy into motion or work a storage batter accumulates chemical energy when it is charged this is changed to electrical energy when you press the starter button to turn over the motor and when you step on the gas the chemical energy of the fuel is changed by combustion into heat energy in the motor which moves the car let's examine this subject of heat as a form of energy in this laboratory demonstration we can see Heat doing work this turbine wheel is matter at rest heat from the bunson burner will warm the water from about 25° Centigrade on up to the boiling point heat causes the water to turn to steam which expands and moves the turban expansion due to heat is the basic principle behind all kinds of heat engines closely Allied to heat are a number of other forms of radiant energy radiant energy travels through space in waves of different wavelengths you've heard of radial waves and television the energy travels in wavelength from a qu of a mile long down to a few feet in length infrared Rays a form of heat are radiant energy with a wavelength shorter than 100th of an inch still shorter are the waves of visible light from the longer red rays through the Spectrum to Violet ultraviolet such as the tanning rays of the sun is energy with an even shorter wavelength X-rays and gamma rays can travel through opaque objects and are extremely short about 1 billionth of an inch all these waves are forms of radiant energy we also use energy in the form of electricity here in a simple motor that anyone can build we see motion caused by the flow of electricity electrical energy can be used to do work to operate such machines as this street car the energy to move a street car must be brought from somewhere through wires from an electric plant perhaps a Coal Fired Steam Plant or a hydroelectric plant here electrical energy is obtained from the kinetic energy of falling water and the whole system from water to street car might be thought of as a single machine a machine that transforms the potential energy of water behind a dam into the kinetic energy of a moving street car and the transformation of energy from one form to another is the whole story of our practical uses of energy we have devised a great variety of appliances tools machines and engines designed to make use of various forms of energy but what are the sources of our Energy natural fuels such as coal are one important Source ages ago energy from the sun which accumulated in green plants formed the coal we use today falling water may also be called a source of energy but how did the water get where it could fall heat from the Sun furnishes the energy which evaporates water from oceans and lakes so that it can fall as rain and flow in our Rivers so the sun is the original source of most energy heat and light and other forms of radiant energy result from a process in the Sun a process We Believe of transforming matter into energy indications are that simple atoms of hydrogen in the sun are being built up into heling I giving off enormous quantities of energy in the process this type of energy is called nuclear energy or sometimes atomic energy from the nucleus of the atom comes the explosion of the atomic Bond but we can demonstrate some very gentle effects of nuclear energy we use a device like this to measure the radiations of nuclear energy indications of such energy are picked up by the tube or probe of this Geer counter they are Amplified in this box and show up as a warning sound on the loudspeaker such a measuring instrument is an important tool in our investigations of industrial and medical applications of nuclear energy now you do not ordinarily think of a watch as radiating energy of course the Luminous dial gives off light visible in the Dark Yet the radium paint also sends out other radiations gamma rays as the nucleus of an atom here and there breaks up we shall hear indications of matter atoms of radium being transformed into [Music] [Music] energy we can also see indications of this radiation of nule nuclear energy Rays given off by the radium atoms cause this needle to [Music] move and so we've learned a little about our sources of energy and the forms it may take we've seen potential energy the energy of position transformed into kinetic energy the energy of movement we've seen an example of chemical energy heat energy electrical energy and nuclear energy matter transformed into energy in this picture we've shown just a few examples of different forms of energy wherever you see work being done find out how energy is being transformed and how it is being applied what can you learn about the nature of energy [Music]