Explaining Shutter Speed to Scouts

I am currently helping my son's scout group to achieve their photographer's badge. Last week I explained the workings of a camera, and it amazed me in this digital age just how fascinated the boys were by the film cameras. We then had great fun experimenting with shutter speeds. Here are 3 shots taken, all at the same exposure, all with the camera in the same position on a tripod, to demonstrate how when you use a slow shutter speed, subject movement is captured. 

first I told Henry to still really still...

.... then move! 

... good fun!