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Lesson 1: Electrical Energy

Introduction

In this lesson we'll see that batteries are a store of energy and transfer energy to components in a circuit.

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Types of energy conversion

Electricity is important because we can use it to make so many things work.  That's why we talk about electrical energy.  For example, a bulb converts electrical energy into light energy, a motor converts it into movement energy and a speaker converts it into sound energy.

It's important to remember that electrical energy is a form not a source of energy because it can't easily be stored.  Ultimately electrical energy has to come from a long-term store like the chemical energy in coal.

In a battery the energy comes from chemical reactions.

There is a debate about whether to use the word 'convert' or 'transfer' when we talk about energy.  It's also not quite right that a motor simply converts electrical energy into movement energy.

Whenever energy is moved around some of it is always wasted as heat.  That's why light bulbs can get too hot to touch.  This idea of energy ending up as heat is tied up with the conservation of energy.

When a bulb or motor or speaker is working then energy is transferred from the battery to the device.  So you can think of batteries as storing energy rather than storing charge.

Brighter bulbs transfer energy quicker

Some bulbs are designed to be brighter than other bulbs when connected to the same size battery.  The brighter bulb will run the battery down first because it's taking energy from the battery quicker.

Energy is transferred quicker if a battery has to run lots of things

Batteries can also be made to run more than one bulb at once.  The more things a battery has to run at once the quicker it has to transfer energy and the faster it runs down.

Back to Summary of Electricity Explained