Why Does Electricity Flow?

Transcription

1 Why Does Electricity Flow? Topic 1: What is current electricity and how is it made? Key language electron flow circuit battery generator turbine nuclear fission shaft copper coil power line First ideas See Introduction for suggestions on how to introduce the Factbook for the first time. Mixed ability teaching See Introduction for suggestions on how to use the activities identified by the and icons. What you need A copy of the worksheet Vocabulary for every child. A copy each of the two worksheets How current electricity is made in a traditional power station and How electricity is made in a wind farm for every child, plus A3 copies for yourself. Before reading Worksheet: Vocabulary Tell the children that they are going to read about electricity and give out the worksheet, which introduces some of the key vocabulary. The children should be able to guess all the correct answers. Ask the children to check their answers with a partner before you go over them with the whole class. Get the children to circle the correct pictures and to read out the correct definitions aloud. Answers: 1b, 2a, 3b, 4c, 5a Reading Read pages 4 and 5 of the Factbook, pausing to discuss and explain the concepts, for example, by getting the children to point to the correct definitions and pictures on their worksheets as you come to those words. Alternatively, play the CD (track 33) instead of reading, pausing where necessary. The children could then reread the sections to themselves or in small groups. Ask some of the more confident children to read a short section aloud to the class. After reading Worksheets: How current electricity is made in a traditional power station and How electricity is made in a wind farm Give out Worksheet 1: How current electricity is made in a traditional power station. The children look at the sentences at the bottom of the page and copy them onto the appropriate place on the diagram. Display your A3 copy of the diagram to go through the answers with the children. Repeat with Worksheet 2: How electricity is made in a wind farm. Go through the answers with the children first, using your A3 copies of the worksheets, before asking them to copy the sentences. White out some of the words before photocopying the worksheets for the children. Write the words on the board and ask the children to write the labels on the diagrams and fill in the gaps. 59 Answers: 1d, 2b, 3a, 4e, 5c Answers: 1d, 2c, 3b, 4a, 5e

2 Additional activities Simplified questions and answers (page 69): See Introduction for suggestions on how to use these. 60

3 Name Worksheet: Vocabulary Guess what the words mean. Circle a letter. 1. An electron is: a. a monster from the planet Electrica. b. a little bit of an atom that carries a negative electrical charge. c. a kind of police officer. 2. An electrical circuit is: a. a path that that can carry electricity. It can have branches, but it must be closed somewhere. b. the money we pay for our electricity. c. a kind of circus. 3. A turbine is: a. a large animal that lives in the sea. b. a motor that turns a shaft. c. a kind of plant. 4. An electricity generator is: a. a kind of fish. b. a kind of soldier. c. a machine that makes electricity. 5. A coil is: a. something such as wire that goes round and round like this. b. a bottle of oil. c. a very nice phone. Cambridge University Press 2010 PHOTOCOPIABLE 61

4 Name Worksheet 1: How current electricity is made in a traditional power station Write the sentences a. The turbine turns a shaft. b. The steam then turns the turbine. c. Power lines carry the electricity to our homes. d. Oil, gas, coal or nuclear power are used to make steam. e. The shaft turns a magnet round a copper coil. This makes electricity. Cambridge University Press 2010 PHOTOCOPIABLE 62

5 Name Worksheet 2: How electricity is made in a wind farm Write the sentences a. The shaft turns a magnet round a copper coil. This makes electricity. b. The movement of the blades is used to turn a shaft. c. The wind turns the blades. d. The wind blows. e. Power lines carry the electricity to our homes. Cambridge University Press 2010 PHOTOCOPIABLE 63

6 Topic 2: Static electricity and current electricity Note: This follows on from Topic 1. Key language occur naturally flash spark static electricity build up of electrical charge electrons opposite charge gigantic electric spark release energy gain/lose something stick up First ideas See Introduction for suggestions on how to introduce the Factbook for the first time. Mixed ability teaching See Introduction for suggestions on how to use the activities identified by the and icons. What you need Some inflated balloons. Three pieces of paper about 10 cm by 15 cm for each child. A copy each of the worksheets Static electricity and current electricity and More facts about static and current electricity for every child. Before reading Review the meaning of electron and circuit from Topic 1. Here are examples of how you might introduce some of the key language, writing new vocabulary on the board throughout: Pass the balloons round the class and encourage the children to run them over their hair as fast as they can. Ask Why is our hair sticking up? to elicit or introduce static electricity. Reading Worksheet: Static electricity and current electricity Give out the pieces of paper and ask the children to write True on one, False on the next and Don t know on the third. Put the children into pairs and give out the worksheet. Ask them to go through the sentences and decide whether they think they are true or false. Encourage the children to discuss the sentences. When everyone is ready, read out the sentences one by one and ask the children to hold up their True, False or Don t know signs. Read pages 6 and 7 of the Factbook, pausing to discuss and explain the concepts, for example, contrasting the opposite charges that cause lightning with the same type of charge that causes our hairs to repel each other when we brush electrons into our hair with the balloon. Alternatively, play the CD (track 34) instead of reading, pausing where necessary. Read through the true or false sentences and get the children to vote again. Give them the correct answers and get the children to make any corrections on their worksheet. The children could then reread the sections to themselves or in small groups. Ask some of the more confident children to read a short section aloud to the class. Answers: 1. T 2. T 3. F. (It is about 9.65 km long.) 4. T 5. F. (You brush electrons onto it.) 64

7 After reading Worksheet: More facts about static and current electricity Give out the worksheet. The children write S or C by each sentence. If you like, ask the children to write S on the back of one of their pieces of paper and C on the back of the other. To go over the answers, read out each sentence in turn and ask the children to hold up their C or their S. Give the correct answer and get the children to make any corrections on their worksheet. Additional activities Simplified questions and answers (page 69): See Introduction for suggestions on how to use these. Further reading: You could now read Lightning strike on page 14 of the Factbook. Answers: 1. S 2. C 3. C 4. S 5. S 6. C 7. S 8. S 65

8 Name Worksheet: Static electricity and current electricity Are the sentences true or false? Write T or F. 1. Lightning is caused by static electricity. 2. A stroke of lightning is hotter than the surface of the Sun. 3. The average stroke of lighting is about a kilometre long. 4. In current electricity, the electrons flow around a circuit. 5. When you run a balloon over your hair, you brush little wires onto it. Cambridge University Press 2010 PHOTOCOPIABLE 66

9 Name Worksheet: More facts about static and current electricity Here are some facts about static and current electricity, but they are all mixed up. Write S for static or C for current. 1. It is caused by a build up of electrons. 2. It is the kind of electricity in a battery. 3. It needs a closed circuit to flow. 4. It stays in one place until it jumps to an object. 5. It causes lightning. 6. It powers computers, fridges, lights and TVs. 7. It doesn t need a circuit. 8. It s the kind that gives you a shock when you walk across a rug and then touch a door handle. Cambridge University Press 2010 PHOTOCOPIABLE 67

10 Topic 3: Batteries Note: This follows on from Topic 2. Key language store something battery immediately tiny huge chemical reaction go flat First ideas See Introduction for suggestions on how to introduce the Factbook for the first time. Mixed ability teaching See Introduction for suggestions on how to use the activities identified by the and icons. Before reading Here are examples of how you might introduce some of the key language, writing new vocabulary on the board throughout: Show the children your watch, mobile phone and laptop and ask What makes these things work? What do they all have inside them? to elicit or introduce batteries. Brainstorm and write on the board all the things you and the children have at home and at school that are powered by batteries, using a bilingual dictionary or little sketches for unknown vocabulary. Decide with the children which of the things have tiny batteries. Also mime trying to make a call on a mobile phone but failing because the battery has gone flat. Reading Read pages 8 and 9 of the Factbook, pausing to discuss and explain the concepts, for example, by guessing how big the battery that runs an electric car is. Alternatively, play the CD (track 35) instead of reading, pausing where necessary. The children could then reread the sections to themselves or in small groups. Ask some of the more confident children to read a short section aloud to the class. After reading Demonstrate how to make a battery from a lemon. See page 9 of the Factbook and also Useful link. Additional activities Simplified questions and answers (page 69): See Introduction for suggestions on how to use these. Further reading: Read First electric car on page 12 and Electric force: Alessandro Volta on page 16 of the Factbook. Useful link 68 What you need A watch (battery powered). A mobile phone. A laptop (on battery power). A lemon. A galvanised nail. A copper coin.

11 Simplified questions and answers Q: What is electricity? Q: Why does electricity flow? Q: How is electricity made? Q: Does electricity occur naturally? Q: What s the difference between static electricity and current electricity? Q: What do AC and DC mean? Q: Can you store electricity? Q: Why do batteries go flat? Q: Why do circuit-breakers trip? Q: Why does my mp3 player need an AC adapter? A: Electricity is a type of energy produced by the movement of electrons. A: Electricity flows when there is a source of electrical energy (such as a battery or a generator) connected into a circuit. A: There are many different ways to make electricity. Each method uses a turbine which turns a shaft and moves a large magnet around a copper coil. This movement creates electricity in the wire. A: Lightning is a natural form of electricity. This flash of heat and light is created by static electricity. A: Static electricity is when electric charges build up but are not flowing. Current electricity has a steady flow of electrons. A: The current that is made by a generator and is carried inside power lines is Alternating Current (AC) electricity. When the power comes from a battery, the current only moves in one direction and is called Direct Current (DC). A: Electricity can be stored in batteries, but not in power plants. A: Batteries go flat when the chemicals inside them can no longer make electrons flow. A: Circuit-breakers trip because they get too hot when too much power is going through them. A: An AC adapter changes the powerful AC electricity from the wall socket to the less powerful DC electricity that an mp3 player needs. The adapter also recharges the mp3 player s internal battery. Cambridge University Press 2010 PHOTOCOPIABLE 69

12 It s quiz time! ideas and answers You will find a quiz on pages of the Factbook. Here are some ways you could use the quiz: Take each activity in turn, with the children working in pairs or threes, checking the answers as a class before going on to the next activity either immediately or in a future lesson. The children work in small mixed ability teams to complete as many of the answers in the entire quiz as they can before checking the answers as a class and seeing which team has won keeping this as light-hearted as possible, of course! The children work in pairs or threes to complete as many of the answers in the entire quiz as they can before checking the answers as a class. The children work individually on the entire quiz and then compare their answers in pairs or threes before checking them as a class. Exploit the quiz as extension activities for your fast finishers. Answer key Activity 1 2. F You have more chance of being struck by lightning than winning the lottery. 3. F The average stroke of lightning is about 9.65 kilometres long. 4. F Electricity was first used in homes in the late 1800s. 5. T 6. T Activity 2 2. Alessandro Volta 3. Michael Faraday 4. Thomas Edison Activity 3 2. Nikola Tesla 3. Alessandro Volta 4. Nikola Tesla Activity 4 1 g 2 e l e c t r i c i t y l n e e 3 c 4 c i r c u i t t a r r 5 t u r b i n e o o e n r n s 6 s t a t i c The mystery word is energy. 70