Conductors and Insulators

Radha’s curiosity

Radha’s father one day was going to check how the work was going on at the house they were building. The house was nearly complete and the only thing left was electrical connections. Radha went with her father that day because she was bored and also that day was a holiday, also her father wanted her to see her new home so both of them went to their new home.

As soon as they entered Radha saw so many wires and switches and many things that she did not know lying on the floor, she asked her father “are these for the current you explained to me about?” to which her father smiled and said yes. Then she recalled what current was, and what caused current and how it flows. 

She was seeing how the workers carefully arranged every wire and every switch, she did not go too close because she knew current and electricity are very dangerous things. She carefully saw everything from a distance and went running to her father and asked, “if the current is just electrons flowing. And from what you said, everything in the universe that we can see has electrons, why don’t we put other things like a cloth or some wood or why don’t we let current flow through the walls? Even the walls have electrons right?”.

Her father was impressed with how his daughter was asking very good questions, he appreciated her and said “you ask very good questions Radha, that is very very good” then he said, “I know I told you that everything has electrons but I never said current can pass through everything”. Radha did not understand, he made her sit on her lap and explained with the water example.

He said, “imagine flowing water as current, now when we turn the motor ON, the water comes from the pipe. If we leave the pipe on the ground, the water just flows away and gets wasted, so we use the pipe to channel and direct the water where to go. We use a pipe because the pipe does not take any water for itself, but it can CARRY the water.

In the same way, everything has electrons but not everything can carry electrons. The materials that can carry the electrons from one place to another are called CONDUCTORS, and the substances which do not carry electrons are called INSULATORS. Radha understood why the wires were being inserted and so much about conductors that day.

Conductors And Insulators

When we take many materials/substances and study them it will be easy to divide them according to their properties and then study them separately. In the same way, materials can be divided into two groups namely conductors and insulators. 

Conductors

All the materials which CAN conduct electricity through them are called conductors.

Conductors are like pipelines. The pipes carry water in them, they help water to reach from one place to another. Conductors are substances that can carry electrical current from one place to another.

Conductors can carry current because THEY HAVE free electrons. Free electrons are the ones that can move freely inside the conductor. We know that for current to flow we need to apply a potential difference/voltage across the conductor. When this potential difference/voltage is applied the free electrons move from one place to another through the conductor. And hence, electricity/current is flowing through the conductor.

Examples of conductors are metals like copper, steel, aluminium, bronze, iron, etc. The wires we see in our houses, above the roads, and many other places, they all are made of metals.

Insulators

All the materials which DO NOT/CANNOT conduct electricity through them are called insulators.

Insulators are a complete opposite to what conductors are. Conductors carry current through them and insulators DO NOT CARRY current through them. They do not allow current to pass through them. Where conductors have free electrons that can move freely and can help current flow through the conductors, insulators DO NOT HAVE FREE ELECTRONS.

Examples of insulators are glass, wood, plastic, porcelain, stones, etc.

Quiz

1) What type of materials allow electrical current to flow through them

  • Conductors
  • Everything that has electrons
  • Insulators
  • Semi-conductors

2) What type of materials DO NOT allow electrical current to flow through them

  • Conductors
  • Materials that have free electrons
  • Insulators
  • Materials with no electrons

3) What is required for a material to be a conductor

  • Weight
  • Speed
  • Free electrons
  • Static protons

4) Insulators cannot conduct electricity because they do not have free electrons which can carry the current(        )

  • True
  • False

5) Every metal is a conductor (           )

  • True
  • False
  • Depends on if the metal has free electrons
  • Does not depend on free electrons

6) Examples of Insulators are

  • Copper, aluminium, wood
  • Wood, plastic, aluminium
  • Plastic, iron, glass
  • Plastic, porcelain, wood

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