Pull the string towards you to make the disc whirl around. How fast can you make it go? A popular toy which can be made with a variety of materials. Heavier discs need better quality string.
Please download the pdfs for up to date instructions.
Making the toy
1) flatten your bottle top rim in or out but keep it even and 2) make two holes in the top an even distance from the centre
3) thread 70 cm (30 inches) of cotton thread through the holes and tie
Playing with the toy
1) wind the thread by holding both ends loosely and evenly making the disc turn a circle and twist the thread up.
2) now pull the string out to make it unwind and spin the disc just before the twists run out. It is essential to slacken the string so the twists can wind themselves back up.
This toy does prove difficult at time, once the disc is spinning fast it rewinds very easily. Getting there is sometimes requiring patience so keep trying.
It is best to do a lot of winding initially.
There must be an even even number of twists on both sides.
The disc needs to be balanced and the holes equidistant from the centre.
The thread must not be too stiff to allow the winding to take place.
The thread will break if its too weak or the holes are too sharp
Developing this toy
Can you do this with one side looped over a peg?
Try using larger discs, thin plywood is excellent! Keep it balanced though.
Attach one or two discs together on the string to make a heavier disc
Decorate the faces of larger discs, longs spirals work very well
Make notches on the edge, hear the sound when brushed against other materials
Why it works
Whizzers work by giving the disc momentum and turning that into the twists on the string which pulls the string closer. Pulling apart makes the string unwind which spins the disc.
Air resistance is caused by any imperfections on the disc and any wobbling of an out of balance top.
Gyroscopic forces can be felt when this disc is going fast, it becomes ‘Weightless’ and doesn't respond instantly when you move.