• What are the best conductors?
  The best conductors are metals like copper and silver. Water is also ...

• What is a semi-conductor?
  Semi-conductors are materials such as silicon or germanium, which are ...

• Who invented transistors?
  Transistors were invented by three scientists working at the Bell ...

• What is a volt?
  Electrical current flows as long as there is a difference in charge ...

• What is resistance?
  Not all substances conduct electric currents equally well. Resistance ...

• What is an alternating current?
  A direct current (DC) flows in one direction only. Most hand-held ...

• How does electric light work?
  An electric bulb has a very thin filament of tungsten wire inside a ...

• What is a magnetic field?
  The magnetic field is the area around the magnet in which its effects ...

• What is a lodestone?
  Thousands of years before people learned how to make steel magnets, ...

• What is conduction?
  Conduction is one of the three ways in which heat moves. It involves ...