Energy and our Universe - Pearson Schools

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56 (a) (b) BTEC’s own resources 2.10 Producing electrical energy – batteries In this section: Activity A Write down three appliances you have used today that are powered by batteries. Were the batteries rechargeable or non-rechargeable? Did you know? A battery produces electricity by the chemical reactions that take place inside it. The chemical inside a battery is called an electrolyte. Batteries can be rechargeable or non-rechargeable. Symbols for (a) a cell and (b) a battery. P6 You have probably used something powered by a battery today – your alarm clock or watch, mp3 player or a remote control. If you look at a battery you will see two terminals. One is a positive terminal, called the anode. The other is a negative terminal, called the cathode. In some batteries, such as AA, C and D batteries, the ends form the terminals. Table: Examples of different types of batteries and where we use them. Appliance Battery material Battery type Mobile phone Lithium ion Rechargeable Modern car Lithium acid Rechargeable Very old car Lead acid Rechargeable Laptop Lithium ion Rechargeable Television remote control Alkaline Non-rechargeable Watch Lithium-iodide Non-rechargeable The electricity produced in batteries is described as direct current (dc). Direct current fl ows in one direction and does not change direction. Non-rechargeable batteries A battery is made up of a number of cells. For example, the popular AAA battery is a single cell (although we call it a battery) that supplies 1.5 V. The fl at PP3 is a battery that consists of six 1.5 V cells connected in
series. It therefore supplies 9 V. Non-rechargeable batteries contain what are called dry cells. A dry cell is shown on the right. A chemical reaction takes place between the electrolyte and the anode which produces electrons at the anode. These electrons want to flow towards the cathode where there aren’t many electrons, but the salt bridge is in the way. When a wire is placed across the electrodes, the electrons flow through it from the anode to the cathode generating current. The chemicals are gradually used up, until there are none left to produce charge. The battery then stops working. We use non-rechargeable batteries for items that need little current, such as remote controls, or for things that we don’t use often, such as an emergency torch. These batteries are cheap and don’t lose their energy (called self-discharge) as quickly as rechargeable batteries. However, they do contain chemicals that are harmful to the environment if they go into landfill. Unit 16: See page xxx for information about making batteries. Activity B What kind of electricity is produced by a battery? Why does it have this name? Rechargeable batteries Cells in rechargeable batteries are called secondary cells. These batteries are mostly used in portable items that are used regularly, such as mobile phones and laptop computers. The chemical is used up as the battery is used, but in this case the process is reversible. The battery can be recharged by applying an electric current to it, which reverses the chemical reactions that take place during its use. Assessment activity 2.10 P6 1 Explain the difference between a rechargeable and a nonrechargeable battery. Give five examples of uses of each. P6 2 Draw a labelled diagram of a primary cell. P6 3 Discuss with a partner the advantages and disadvantages of rechargeable and non-rechargeable batteries. P6 Grading tip To meet part of the grading criterion for P6 , make sure that you include a diagram for the primary cell. To get all of the P6 criterion you need to also describe another way of generating electricity. Cross-section of a dry cell. Unit 2 Energy and our Universe metal or graphite cathode electrolyte paste paper or cardboard salt bridge metal (often zinc) anode Safety and hazards Dead batteries must be disposed of safely. Some batteries contain toxic mercury that may leak into the environment. Leaking batteries may also cause burns if the acid inside comes into contact with skin. In some areas of the UK, all types of battery can be recycled. A rechargeable car battery. 57
Page 1 and 2: Credit value: 5 2 Energy and our Un
Page 3 and 4: How you will be assessed Your asses
Page 5 and 6: Energy transformations We need ener
Page 7 and 8: The block diagram shows you that th
Page 9 and 10: Activity A Imagine heating up some
Page 11 and 12: WorkSpace Principal Manufacturing E
Page 13 and 14: Saving our world’s energy resourc
Page 15 and 16: The frequency and period of a wave
Page 17 and 18: Method of transmission Examples Adv
Page 19 and 20: Gamma () radiation Gamma radiation
Page 21: Ohm’s law Ohm’s law describes h
Page 25 and 26: N slip rings A simple ac generator.
Page 27 and 28: Activity B Compare the efficiencies
Page 29 and 30: Activity A Which objects in the nig
Page 31 and 32: Expansion of the Universe Many astr

Energy and our Universe - Pearson Schools

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