An explanation of the difference between direct and alternating current. The clip includes a short historical outline of the work of Thomas Edison and Nikola Tesla. This is followed by an explanation of how transferring electricity over greater distances using DC results in loss of energy. By using AC the voltage can be stepped up, reducing energy loss.

This clip is from:
Bitesize Secondary, Science 1
First broadcast:
28 February 2008

Discuss the difference between alternating current and direct current . Students could investigate differences between the two using an oscilloscope. The idea of stepping up and stepping down electricity for transmission could be explored in more detail and the role and workings of transformers looked at. Practical exercise could build up students' understanding of monitoring and measuring a.c. and calculations involving peak and r.m.s. values carried out.