Electromagnets and the number of coils
The hypothesis that the voltage induced in a coil under the influence of the magnetic field of a moving magnet will increase if the number of turns in the coil is increased is proven to be true. The induced voltage in the coil is found to be proportional to the number of turns in the coil.
The use of magnetic induction can be found in electromagnets, motors and transformers. Hydroelectric power stations and wind turbine generators apply the same principle to convert the mechanical energy of a rotating shaft connected to a magnet into electricity.
The science fair project can perhaps be repeated by varying the speed of the screw driver.
This experiment can also be modified by keeping the magnets in a fixed position and instead, rotating the coil.
Electromagnetic induction - http://electricitymagnetism.suite101.com/article.cfm/magnetic_induction
How to generate free electricity using magnets - http://www.articlesbase.com/diy-articles/how-to-generate-free-electricity-using-magnets-1038086.html
Basic safety requirements