ELECTRIC CIRCUITS Lorem Ipsum tips for learning success. Self-assess student s progress. Provide multimodal input. Learn autonomously

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1 ELECTRIC CIRCUITS

2 ELECTRIC CIRCUITS Lorem Ipsum 2 10 tips for learning success Provide multimodal input Learn autonomously Maximize language exposure Deal with real problems and find real solutions Be aware of the importance of community knowledge Use of authentic material and resources Acquire knowledge through ICT Transfer knowledge to real-life situations Carry out activities that are challenging and require thinking Self-assess own progress Self-assess student s progress

3 ELECTRIC CIRCUITS Lorem Ipsum 3 Read in pairs Electrical circuits can be represented by circuit diagrams. Standard symbols are used to show the various electrical components in the circuit. Components can be connected in series, or in parallel. Standard symbols The diagram below shows the standard circuit symbols you need to know. Circuit diagrams Two things are important for a circuit to work: There must be a complete circuit There must be no short circuits To check for a complete circuit, follow a wire coming out of the battery with your finger. You should be able to go out of the battery, through the lamp and back to the battery. To check for a short circuit, see if you can find a way past the lamp without going through any other component. If you can, then there is a short circuit and the lamp will not light. There are two different types of connections in circuits: series and parallel connections. Series connections Components that are connected one after another on the same loop of the circuit are connected in series. The current that flows in each component connected in series is the same. The circuit diagram shows a circuit with two lamps connected in series. If one lamp breaks, the other lamp will not be lit. Parallel connections The diagram shows a circuit with two lamps connected in parallel. If one lamp breaks, the other lamp will still be lit. Because a parallel circuit has more paths for charges to flow along, the current is greater, and the resistance of the whole circuit is smaller.

4 ELECTRIC CIRCUITS Lorem Ipsum 4 Activities Recalling 1. Which of the following circuits are connected in series and which are connected in parallel? Circuit 1 is connected in Circuit 2 Circuit 3 Circuit 4 2. Read this text and answer the questions. An electric fuse is a device which is used to limit the current in an electric circuit. The fuse safeguards the circuit and the electrical appliances from being damaged. The fuse wire is generally an alloy of lead and tin. It has a low melting point and breaks the circuit if the current exceeds a safe value. The thickness and length of the fuse wire depends on the maximum current allowed through the circuit. It is connected in series in the beginning of the electric circuits. When the circuit current exceeds a specified value due to voltage fluctuations or shortcircuiting, the fuse wire heats and melts. Thus it breaks the connection as shown in the figure and no current flows. This prevents damage to the appliance. a) What is this text about? b) What are fuses made of? c) How can we know that a fuse is damaged?

5 ELECTRIC CIRCUITS Lorem Ipsum 5 UNDERSTANDING 3. Transfer this circuit to a schematic diagram using the standard symbols In this picture the fuse is 250mA. a) When a switch is closed, is the electricity through the fuse the same or does it increase? b) If each bulb consumes 100 ma, how many light bulbs can be connected without melting the fuse? 5. Do you think the bulbs from these two circuits connected in series would shine with the same intensity? Discuss it with you partner and justify your answer. Circuit 1 Circuit 2

6 ELECTRIC CIRCUITS Lorem Ipsum 6 APPLYING 6. Draw an electric circuit that would represent the electric installation of your class. Could you make any improvements? 7. Set up the circuit shown and answer the questions. a) Why do the lamps not light up? b) What will happen if an additional link is added as shown below?

7 ELECTRIC CIRCUITS Lorem Ipsum 7 Revision Video. Series and parallel connections Identify the connections shown in the video and classify them in the chart. Series connections Parallel connections Combination of series and parallel connections Electric circuits. Play and explore

8 ELECTRIC CIRCUITS Lorem Ipsum 8 Extension The light bulb The light bulb is probably one of the most significant inventions in science. It has changed the world by letting people do work at night. Previously this was very hard to do because other light sources (such as candles or fires) did not provide enough light. The full impact of the light bulb is much larger than only reading or writing at night. Travel: Night travel by automobiles has largely been made possible by the light bulb. Also, light houses all over the world use very powerful light bulbs, and this provides the right guidance for all ships. Medicine: All internal and non-intrusive medical procedures use variants of the original light bulb. Mining: Earlier, underground miners used torches, which also added to the carbon dioxide content in the air, and therefore made breathing difficult. With the advent of the light bulb, mining has also become healthier and safer. In coalmines, the risk of explosion of the coal dust contained in the air was so high that conventional fire lanterns couldn't be used (they used tepid metal mesh covered lanterns), with light bulbs coal mining became much safer. War: The development of the light bulb allowed searchlights to be built which could find enemy aircraft, eliminating the risk of being bombed by surprise. Apart from this, the light bulb is used in various other fields including communications, sports, etc. to_be_developed_before_it_could_be_created.3f_2 In groups investigate what ideas or inventions had to be developed before if could be invented. You can find information about the light bulb in the following webpages: Your feedback: The inventions or ideas that had to be developed before the light bulb could be invented are

9 ELECTRIC CIRCUITS Lorem Ipsum 9 Project: Collaborative problem solving Many interesting circuits can be set up with switches in series and in parallel with components. Materials needed Cells, 1.5 V, with holders, 3 Lamps with holders, 3 Switches, 2 Leads, 4 mm, 7 Ammeter (optional) Instructions a) Set up the circuit shown. What happens when the switch is turned on and off? b) Investigate the effect of moving the switch to different points in the circuit. c) Investigate some more complex circuits including two switches. d) Summarize your findings. e) Discuss your findings with your partners.

10 ELECTRIC CIRCUITS Lorem Ipsum 10 Assessment tools Rubric CATEGORY Knowledge - You demonstrate Series/Parallel understanding with some effectiveness. Circuits Application of Knowledge Application - Building Circuits Information Gathering Group Cooperation You thoroughly demonstrate understanding with a high degree of effectiveness. You are able to apply your knowledge to a given situations You are able to design and build a circuit with high degree of effectiveness. You took information from 3 or more sources describing inventions related to the bulb. You participated in all aspects of the collaborative solving project. You ve worked well with others, are on task during the activity and listen to and respect others' ideas and share your own. You demonstrate understanding with considerable effectiveness. You are able to apply most aspects of your knowledge to a given situation You are able to design and build a circuit with considerable effectiveness. You took information from 2 or more sources describing inventions related to the bulb. You participated in most aspects of the collaborative solving project. You were a team player during most of the activity. You kept the group on task for most of the activity. You were willing to help but reluctant to share ideas. You is able to apply some aspects of your knowledge to a given situation You are able to design and build a circuit with some effectiveness. You took information from 2 or more sources but not specifically describing inventions related to the bulb. You participated in some aspects of the collaborative solving project. You put little effort into helping the group solve the problems. You did not share ideas. You did not listen to others in the group. You demonstrate understanding of series and parallel circuits with limited effectiveness You is able to apply little aspects of your knowledge to a given situation You are able to design and build a circuit with limited effectiveness. You took information from only one source and/or information not accurate. You did not participate in the collaborative solving project. You were hostile or unable to cooperate with your group.

11 ELECTRIC CIRCUITS Lorem Ipsum 11 Personal portfolio Identify and write your own profile in every category. Electric circuits Knowledge - Series/Parallel Circuits How can I improve? Application of Knowledge Application - Building Circuits Information Gathering Group Cooperation

12 ELECTRIC CIRCUITS Lorem Ipsum 12 Checklist In this unit you have Used text, videos and pictures to get information Acquired concepts autonomously Maximized your language exposure Found solution to real situations Seen the importance of group cooperation Used authentic material and resources Used ICT to acquire knowledge Applied your knowledge to build a circuit Done challenging activities that required thinking Self-assessed your progress