Torches is a standard primary project.
This version uses a brand new material, QTC, and an LED instead of a power hungry bulb. It also uses a long life CR2032 coin cell battery.
Finished torch
Torch as bookmark
Alternative shapes possible
If you usually do this project with bulbs and batteries, try this instead, it lets you make a flexible neck torch which can be used as a book light, and can be adapted to include shape exploration and materials research.
Click on the picture for a PDF file showing how the torch is assembled
All components were bought from Rapid Electronics and are as follows
CR2032 lithium coin cell battery - Use unbranded type as they are cheaper
3mm LED - Any type but white ones work best. DO NOT buy super high power red or orange as they can temporarily dazzle children as they are so bright. LED's are 'polarised' components which means power has to flow through them the right way. If yours don't work, swap the wires round.
LED holder - This greatly simplifies assembly but can be stiff to assemble the LED's wires into
Sticky back plastic
Foil
A battery holder. i had these laser cut for the primary school by a local secondary school but you can also punch a hole out of any other corrugated card or bend a strip of card round the battery instead
QTC - This is a revolutionary compound which acts like a pressure switch. When not pressed, or very lightly pressed, it has an insulating value as high as plastics. When pressed down it conducts like metals. As you vary the pressure, you vary the power going through it and you so can vary the light level by pressing harder or softer.
How it works is mind bogglingly complicated and probably irrelevant to pupils, I teach that it is a magic square that controls the flow of electricity.
QTC comes in various forms but the small square 'pill' for about 35p is the one to use
