磁界の中でコイルを回すと、コイルを横切る磁界の変化がコイル中の電子に力を与え動きます。すなわち電流が流れます。発電所ではこの原理を使って発電しています。コイルの動かす場合と、磁石を動かす回す場合の２種類の人力発電を体験できます。 If you take coils of wire and make them rotate in a magnetic field, electricity will flow through those wires. This happens because the electrons in the wires are pushed along by changes in the magnetic field they travel through. By moving these wires back and forth, or around and around, you can make your own electricity in two different ways!