Topic 10 Making Electricity

Aim: To learn more about the batteries we use everyday

Electricity is the most widely used form of energy in the home and in industry. Usually we generate electricity from burning fossil fuels, harnessing the power of water (hydroelectric), or nuclear energy. However, many of the things we use that need electricity for, have to be carried around with us. e.g. personal stereos, mobile phones

Inside a battery there is a mixture of chemicals. When these chemicals react, they produce electrical energy. When electricity is produced, electrons flow from the battery, through the wires, to the device to which it is connected. In most batteries the electrons come from a layer of zinc metal. What about portable electricity? -We use batteries.

An electric current is a flow of electrons. Chemical reactions in a battery produce electricity

Inside a battery there is a mixture of chemicals. When these chemicals react, they produce electrical energy. When electricity is produced, electrons flow from the battery, through the wires, to the device to which it is connected. In most batteries the electrons come from a layer of zinc metal.

The Dry Cell Battery The dry cell battery is most commonly used for radios, torches etc. The zinc cup forms the negative terminal of the battery while the carbon rod is the positive terminal. In-between the two terminals is a paste of ammonium chloride. This paste completes the circuit by allowing ions to flow through it – it acts as an electrolyte.

In a dry cell, the chemicals are used up. This means that dry cell batteries have to be replaced regularly. Some batteries are re-chargeable. This means that the chemicals can be restored by giving the battery a supply of electrons. e.g. a car battery contains lead metal. When the battery is being used the lead metal atoms turn into ions. During recharging, the ions are turned back into lead atoms. An electrolyte is a substance which allows electricity to pass through it.

Advantages of BatteriesDisadvantages of Batteries Portable Safer Can save lives (pacemakers) Can be used up Limited power supply Expensive Uses metal resources Disposal of poisonous chemicals

A Lemon Cell Lemon juice is an acid and so it is an electrolyte. Electricity is produced when different metals are connected by an electrolyte. When an electric current passes around a circuit this is a flow of charged particles. Magnesium Copper

In the wires: there is a flow of electrons. In the electrolyte- there is a flow of ions. A cell is two metals separated by an electrolyte. Magnesium Copper

Lead-Acid Battery (used in cars) Electricity is produced by a chemical reaction. Chemicals get used up by the reaction so there is a need to replace them because the battery becomes ‘flat’. Lead-acid battery is rechargeable. Lead electrodes Sulphuric acid (electrolyte) The sulphuric acid electrolyte completes the circuit and allows a flow of ions.