Lesson 1: Electrical Energy
In this lesson we'll see that batteries are a store of energy and transfer energy to components in a circuit.
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.
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.