Flow Of Electricity (1946)

the flip of a switch Chris adidas time cleaner electricity toasts our bread and irons our clothes it brings news and entertainment from the far right it gives us light to read and work by and it makes life more portable by operating the everyday machines we depend on so much because we use electricity all the time we hardly ever stop to think about it and too often all we know about it is you plug it in and pull a switch what is electricity and how does it work Betty Browns in trouble her lamp doesn't seem to light how about it Bobby can you help well it would light Betty if you put the plug in the wall that's where the electricity comes from and you must have electricity to make the lamp work but why Betty wants to know and that's where Bobby is stumped let's ask dad he usually knows how to explain things like this sure dad knows the answer Bobby get that little lamp from the workshop and we'll go into the kitchen and here in Dad's hand is something that will give us the electricity to light the lamp it's called an electric cell the two knobs you see at the top are called terminals they are like doors to the cell one terminal is for the electricity to come out and the other terminal is for the electricity to go back in but we know that electricity travels along wires see the lamp has two wires attached to the base when the loose ends of the two wires are passing to the terminals electricity flows out through this terminal along the wires to the lamp making it light but Betty still wants to know what electricity is what's in the wires well electricity is made up of electrons that's what's in the wire Betty electrons electrons are tiny particles so small that we can't see them but here's a drawing of the electric cell the wires and the lamp and he show us what electrons would look like if we could see them see they might look something like this always moving about even though one of the wires is not connected the electrons keep moving about but not going anywhere but when the wire is connected to the terminal the electrons start flowing in one direction they flow along the wire to the lamp where they make the lamp light up pushes them out again the cell doesn't make electrons it just pushes them out as fast as it can this movement round is called the flow of electrons for that's what electricity is very the flow of electrons and when electrons flow and light a bulb or run an electrical appliance we have what is called a circuit a closed circuit this circuit is called a closed circuit because all the wires are connected then there are no loose ends unconnected only where we do have a closed circuit can the electrons flow out of the cell down the wire into the bulb making it light up and along the wire and back into the cell then they are forced out again and keep going around and around in the same path when the circuit is broken at any point the flow of electrons stops so the light goes out when this wire is loose it makes no difference where the circuit is broken it can be here at this terminal or here at this terminal or any place at all in the entire circuit as soon as the circuit is broken the flow of electrons stops and the light goes out as soon as the circuit is closed again the flow of electrons starts and that light goes on but Bobby has a question what about the switch when he pushes it the light goes on that means the circuit is broken when he pushes it again the light goes on that means he has closed the circuit but how he hasn't touched any wires the switch breaks the circuit for him right here inside a switch is just a simple way of breaking or closing a circuit it saves the trouble of unfastening a wire every time we want the flow of electricity to stop end of fastening the wire back every time we want the flow of electricity to start well that's the first part of the story about electrons unless there are any other questions yes Betty wants to know about the lamp cord why is there only one wire instead of two in the circuit dad just explained there were two wires one for the electrons to flow out from the cell and another for the electrons to flow back into the cell aren't two wires absolutely necessary to light this kind of lamp they certainly are Betty without two wires we can't have a closed circuit like this but if you look closely at this small piece of lamp cord dad is holding you'll see that there are actually two wires inside it one here and one here a lamp cord is just two separate wires with a covering around them notice that the wires on all the electric cords you use around the house are covered that's for protection the electricity used at home is strong enough to give you a dangerous shock unless there is a covering or insulation around the metal wires to prevent them from touching you well Betty and Bobby have found the answers to some of their questions they have learned that an electric cell can give us electricity and that electricity is made up of electrons which are tiny particles always moving about they've seen that when a wire is connected here the cell pushes the electrons along the wire into the lamp making it light up along the other wire and into the cell again where they are forced out once more to keep going round and around this movement is called the flow of electrons they know that when the circuit is broken at any point the flow of electrons stops and the light goes out they've seen that a switch is just a simple way of breaking or closing a circuit they found out that there must be two wires in this kind of closed circuit one for the electrons to flow from the cell to the lamp and the other for the electrons to flow from the lamp back to the cell and now there's just one more thing that's puzzling Bobby where is the electric cell in our house is it hidden in the wall do we have several of them and when the cord is plugged into the socket does it connect the wires with the cell well Bobby not exactly there is no electric cell in the wall and gets it to Lexi from something different but the idea is the same there are just two more wires for us to learn about the plug connects the lamp cord with the two wires in the wall like this the wires in the wall lead outside of the house where they join a main line which may be underneath city streets or overhead until they reach a big power house miles a inside the power house is a generator which like the electric cell can also provide electricity by pushing electrons out along the wires but while the electrons that flow from an electric cell can light only a small lamp a big generator can supply enough power or tricity to light many homes so the next time you switch on the lamp in your living room pause for a moment and think isn't it wonderful that we can control electricity and started flowing over a circuit that maybe many miles long to light and lamp or do any one of a thousand tasks which make life simpler and more convenient for us and we can do all this with just the click of a switch