Robots and electric eels Electricity

2 A forest

3 trees

4 What can you see?

5 Do they stay still?

6 No !

7 Now a game ----

8 When the circuit is complete tiny particles move round the circuit. The particles are very, very, very, very, very, very, very tiny!

9 Drawing circuits A battery A lamp

10 The circuit you connected There is a battery and a complete loop of conducting material.

11 Which materials are good conductors?

12 Electricity makes us work

13 Electrophoridae electric eel

14 OW !

15 Water conducts electricity

16 Skin is rough Light pressure – very few contact points meta l

17 Press Heavy pressure – many contact points metal

18 Wet skin metal Water increases contact area between skin and metal

19 Safety Never touch electric appliances or switches with wet hands! If we get a shock we will not work properly any more! When we do experiments we use small batteries NOT mains electricity!

20 No switches in a bathroom X

21 Changes

22 Look at the lump on top of the lamp When it goes dark the street lamp comes on. Special materials are used which change from good conductors to poor conductors. The materials are semi-conductors

23 Semi-conductors have lots of uses

24 LEDs

25 New traffic lights

26 What have we learned? When a current flows, tiny particles move round the circuit. Conductors allow a current to flow through them  Metals, carbon, water, Insulators do not allow a current to flow through them  Wood, plastic, paper,

27 Some materials can be conductors and insulators! These are semi-conductors They are very useful as  sensors - when changes occur they can switch things on or off  LEDs – used in traffic lights  and lots and lots more uses ---

Electricity