Specific charge of the electron explained

Dear Y13
The link below gives a full and comprehensive explanation of how Thomson worked out e/m - use this to make notes on what we were attempting to do on Friday and we will pick up any remaining issues next lesson.  Remember that you only need to be able to describe one method of doing this.

http://www.antonine-education.co.uk/Pages/Physics_5_Options/Turning_points/TP_01/Turning_points_1.htm

Also have a go at the questions throughout the text as they will develop your understanding, and have answers as well.
Thanks
Ms H