Understanding
Series circuit-Aid in understanding circuits and how they function |
Question
Demonstrate how the light in the circuit could be made dimmer/ brighter, using electrical symbols in your illustration? Phase 1 Ask the students for suggestions on how to build a model for the circuit that they drew last lesson with real materials so they can see the electrical circuit. Request the students use the meta-language by restating the components of an electrical circuit and what the symbol looks like (illustrate on scrap paper) to match the component. Model for the students how the circuit works when it is connected to the battery. Teacher information The circuit works because the battery repels the electrons away from the negative charge of the terminal through the wire into the resistor and back to the positive connector in the battery as it is attracted to it, which makes the electricity flow through the circuit without stoping while there is remaining charge in the cell/battery. Phase 2 Ask the students to in groups discuss with their peers, How could the light in the circuit be made dimmer/brighter? Place a variety of materials on the table for the students to see. Long thin wire, short thick wire, 1.5 volt batteries and 3 volt batteries. Ask the students to come up with their own ideas on how to make the light brighter. Bring the groups together and ask students to illustrate and retell to their peer why and how the light was going to become brighter or duller by their action. The class will discuss the illustration and recognise which one they think will work. (PROE RECORDING SHEET. Primary Connections, 2007) The educator would inform the students that putting multiple bulbs on the electrical circuit would create a 'series circuit' . It is formed, when the components are arranged so that a single path for the current to take. The current passes through each component one after another. The potential difference (voltage) across the battery is equal to the sum of all the p.d.'s (potential difference of battery) across the components. A disadvantage of series circuits is that if one component stops working then no current will flow through the circuit"( Prescott, 1999). Teacher information Electricity finds it difficult to pass through some metals, it holds up the electron from flowing through. This effect is called 'resistance'. Electrons flow through some metals better than others. The amount of resistance depends largely on the thickness and length of the wire and what it is made of. If the thread of metal is coiled it will act like a heater. When the wire is resistant (thicker) it creates resistance which causes friction to occur. Where there is friction there will also be heat. As the heat builds up it will radiate the heat outwards. This is what causes the bread to toast in the toaster for breakfast. It is coiled thin wire that has electrons moving very quickly through it to create a red hot heat. In this situation the wire would become dangerous, it is essential to keep a clear eye on every student to make sure they are handling the equipment correctly. Phase 3 Each student demonstrates their knowledge through the creation of a circuit that they can make brighter or dimmer depending on how they construct it. |