Year 7 - Lesson 1 Week commencing 19th March 2012 Electric Circuits Year 7 - Lesson 1 Week commencing 19th March 2012

Title: Electric Circuits WALT – measure the current in a series circuit I must be able to set up a simple series circuit I should be able to measure the current in a circuit I could identify the 3 different types of switches

A simple circuit Demo this then draw the appropriate circuit diag on board

Copy down these components and what they represent No need to write these down. Your prep this week will be to draw a table of symbols using p.291

In a minute you will set up a circuit which will include a switch There are three types you need to know about: SPST switch (the most common you will use) SPDT switch (completes one circuit from a choice of 2) Relay switch (a switch controlled by another electric circuit – a small current starts a larger current). E.g. a reed switch which uses electromagnets – look at p.317

Investigating the current in a series circuit Method Test the current using an ammeter at different points in the circuit Set up the circuit as in the diagram (but with 2 cells). Test the current in three different positions 1) Between the cells and the first lamp 2) Between the two lamps 3) Between the second lamp and the cells Record your results in a table (what should your table look like?) Write a conclusion and answer the questions on the next slide Demo this and draw the circuit diagram on board – including switch and ammeter must be in correct position Need 6 leads per group Ammeter always connects positive to positive side of battery

When you are finished…. Set up a circuit with 2 cells, an ammeter, a lamp and a variable resistor. Turn the variable resistor up and down. What do you notice? Write down what a variable resistor does. Now take out the resistor and add in one or two more bulbs into the circuit. Write down what you observe.

Questions What do you think the electrical energy from the cell is converted into when it reaches the lamp? MBA (Morris Bonus Award) question: If a series circuit is when components are placed one after the other, what do you think about the circuit in this diagram? What do you think happens to the current?

Plenary On your own and in silence – write 5 things that you have learnt today in rough – 1 minute Pair up with your neighbour and discuss your answers – add to your list – 1 minute Pair up with another pair in front of behind you. Share your answers again. Now come back on your own and write in the 5 best answers you’ve heard in your exercise book.