Electronics Course – Switches

Switches

Arrival Craft – Aluminium atom models 

AluminiumModel

Grid colouring sheets.

Introduction: What is electricity? Electricity is a flow of electrical charge, caused by the movement of electrons.

As you saw in your models, atoms are made up of nuclei and electrons. In metals, the electrons on the outermost shell are not very strongly attracted to their nuclei. This means that the electrons can move freely.

We’re going to make a model now to show how the ‘sea of electrons’ allows an electrical charge to flow in a metal.

 

Individual Task: each child should take a plate and stick half a dozen marshmallow halves to it. They can then sprinkle a handful of Millions sweets onto the plate. When they tip the plate, the Millions will flow, around the marshmallow halves from one end of the plate to the other.

ReGroup: Hopefully that gives you a bit of a picture of how electrons flow in a circuit.

We’re going to make another model altogether now.

Give the children a string long enough to pass all the way around the room, with ten or so beads strung on it.

If we pass this bead along the string, we can see how an electrical charge moves along a wire.

We can think of the electrons as beads moving along a string, If they keep moving round and round, the charge keeps flowing round the circuit and it can drive components that we put in the circuit.

What would happen if I cut the string?

If the string is cut, the beads cannot flow anymore.

In order for your circuits to work, they must be complete. Any break in the circuit will stop it working completely.

We’re going to make our very first simple circuits now. I have a small electronics kit for each of you, I’ll be adding new pieces to it as we progress through the course, but we’re going to start with just a few pieces.

Today we’re going to look at buzzers.

Does anyone know how buzzers make a noise?

Buzzers make a noise by vibrating. We’re going to be using piezo buzzers. These have a piezoceramic disc inside them which vibrates when an electric current passes through it.

 

Individual Task: Find the components in the kit and find out their names.

Make a circuit that switches on a buzzer when you touch two wires together.

Break for drink and snack.

 

ReGroup: You’ve made a simple circuit that buzzes when two wires touch. This is the basis for an electronic game.

Show a steady hand game you’ve already made.

I’ve looped one of my wires around the other. When the two wires touch, the buzzer sounds. But, if I can move one wire past the other, without letting them touch, then the buzzer won’t sound.

Would anyone like to have a go with my steady hand game?

Let a child try, briefly.

Individual Task: Make your own steady hand game.

SteadyHandGame

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