What is the link.....

1. What is the link.....

2. Current & Voltage Models AF1 • Understand more about how current and potential difference behaves in circuits • Use and evaluate models of circuits • Work as a team in different roles Ks3 Science Assessment Focus 1: Thinking scientifically Thread 1: Using models for and in explanations Mr D Powell

3. S Mini Whiteboards... • Without talking to another or sharing any ideas draw a complete electrical circuit with symbols including... • two bulbs, cell, and a switch to turn it on and off. • Now draw another one with the same components but make it so that one one bulb can be turned off and the other is on all the time.

4. T Measuring Current Flow... A chemical cell or battery of cells provides a flow of electricity. This flow registers on a meter called an ammeter which counts electrons as they flow through the wires. Can you predict the two other ammeter readings, write it on your board and hold it up.... 0.5A 1.0A 1.5A

5. T Measuring Current Flow... In a series circuit the current is the same everywhere as electrons push around the circuit like water down a pipe. It all travels at the same speed. Can you predict the other ammeter readings? 0.3A 0.3A 0.3A 0.3A

6. T Potential Difference Voltmeters tell us how much “potential” there is in a circuit. What we mean is the potential for an electron to move. We call this “potential difference” as it is the difference in electrical potential. It is the same thing as gravitational potential but for electrons! If each cell is 1.5V what should the voltmeters read.... 4.5V 1.5V

7. What is a Coulomb • Electrons are charged particles and each of them have a very tiny charge or attractiveness of -1.6 x 10-19 C. • If we add a load of them together and think of them as a single “sphere of charge” or ball we get a whole coulomb of charge and can think about defining the ampere or amp 1A = 1C/s e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- C e- e- 1.6 x 10-19 C x 6.25 x 1018 electrons = 1C

8. Mini whiteboards... Without talking to another or sharing any ideas with another person imagine you met an alien and had to explain what an electron was..... Hold it up when you are finished as quick as you can...

9. What happens inside circuits... 4V 1A 1J 1J 1J 1J 1J 1J 1J 1J 1J 1J 1J 1J 1J 1J 1J 1J 1J 1J 1J This is a simple current and voltage model... 1J 1J 1J C C C C = 1 Coulomb of charge C C C C C C C 1J = 1 Joule of energy = 1 Second of time As the Coulombs of Charge move they release their energy as heat and light (through the bulb)

10. Activity – Modelling Circuits... • Instructions... • Work in a team of 5. Your team will be given some information about an electricity model. • It is your job to study this, make a 3D model or diagram and then explain it to the rest of the class. • Each team has a different model. • At the end you all fill in a grid looking at each model as each team explains to the class. • Group Roles • Planner: organise team to complete work in allotted time. • Presenter: writes some notes to explain model to the class or draws a diagram or table of items to help. • Evaluator: watches how team performs and suggests improvements using assessment grid. Tick any boxes achieved. • Maker 4&5:lead producing the model

11. Modelling Electricity One idea to help us explain electricity is to think of a electricity like gravitational potential energy. When you are up high you have lots of it. We can even use diagrams to help us to understand what is going on... transfer to heat energy in resistor Stored chemical energy transfer to heat energy in wires

12. Circuit Rules • Any circuit you can use the idea of the following rules;

13. Level Descriptions for Assessment Focus 1 – Using models for and in explanations..

14. Level Descriptions for Assessment Focus 1 – Using models for and in explanations..

15. Possible Answers

16. Printed Materials • Print one set per group. Ks3 Science Assessment Focus 1: Thinking scientifically Thread 1: Using models for and in explanations Mr D Powell

17. Ski Slope Model.... Skiers are lifted to top of mountain by ski lift which is like a cell or battery Skiers represent the electrons moving in wires current flowing Height of mountain is the voltage of the cell or potential difference Speed of skiers is the amount of current flowing i.e. 1A Skiers convert energy as they ski down mountain like a bulb Skiing pathways are like wires Skiers can take different paths to show resistance

19. Donkey Model.... Gates stop the donkeys When track is wet or muddy Donkey is slowed down Donkeys move along the farmyard tracks (charges) Donkeys speed is current flow They carry bags of hay (energy) to field and other animals to eat Donkeys pick up hay from barn (energy)

22. Trucks Model.... Traffic lights stop them Trucks are like charges moving Trucks deliver goods to customers (energy) Amount of current is speed of trucks Trucks pick up energy at their supply depot (energy) Traffic jams slow them down (resistance)

25. Central Heating Model.... Water pipes are the wires Water flow is the charges moving Flow of water is the current Timer is like a switch for on/off Radiators give out heat (energy) like bulbs Boiler/ Hot water tank is like the cell giving energy

27. Electrical Circuit Model... Resistor or Bulb Wires Pipes Radiator Electric Current Cell Water Pump

28. Runners in Race Model.... Runners are the charges moving Runners recombine to show current at branches Runners speed is the flow of current Runners return to start (cell or battery) Runners lose energy from muscles as they run (energy) Runners can split at branches in parallel circuit Energy lost to surroundings as run Can drink isotonic drink to boost energy

29. Modelling Current Flow.... Current Splits Current Flow = Half Current Flow = Current Recombines +