This week you are going to be making your own torch! In your kit you should have:

• • 1 battery
  • 3 LEDs (Light Emitting Diodes)
  • 2 sticky squares
  • 1 jumbo lolly stick

IMPORTANT: Batteries are very dangerous if swallowed. They should never be left in the reach of a child 3 or under and you should never put them in or near your mouth. If anyone swallows a battery they should go immediately to their nearest emergency centre.  You will need:

• Felt tip pens (optional)

Testing your LEDs

• In your pack are 3 different LEDs – all different colours. Let’s find out what colours you’ve got!
• Hold up your LED. Can you see that one ‘leg’ is longer than the other? The legs are the metal spikey bits! LEDs only work in one direction. The long leg needs to be touching the positive side of your battery and the short leg needs to be touching the negative side of your battery.
• Can you find the positive side of your battery? It’s the side with the + on it.
• Hold your LED so that the long leg is touching the positive side of the battery and the short leg is touching the negative side of the battery (the bumpy side). It should light up! If you need help, watch the video below.
• Test all your colours. Choose your favourite and put the other two to the side.

Putting the torch together

• Your stick is going to be your handle. If you want to colour it in or decorate it, do this now.
• Take one of your sticky squares (the other one is a spare) and peel the backing off one side. Stick this down to one end of your stick (like in the picture).
• Pick up your battery and put the legs of the LED either side of it so that it will work, remembering long leg to positive side. Peel off the other side of the sticky square and stick the LED and battery down on the stick so that one leg is trapped between the stick and the battery.
• Lift up the top leg so that it is not quite touching the battery so your torch is off.
• When you want your torch on, use your finger to push the top leg of the LED onto the battery. When you want your torch to be turned off, release your finger and if it doesn’t go off, bend that top leg up slightly. This breaks the circuit.

Here is Chemical Cress with a video showing you the science behind how LEDs and circuits work and also with a bit of extra help if you are struggling. [embedyt] https://www.youtube.com/watch?v=hB_7kugHzns[/embedyt] Enjoyed this kit? Visit our shop for more weekly science kits