The link below is a video of the g-ball in action.
There are all sort of errors involved, but it’s still reasonably accurate and errors can often serve to act as source of further discussion.
I like it in that it takes away all the confusion associated with the traditional circuit which I think distracts from the important physics (drop a ball; measure time of fall and distance traveled and from this work out g using a very simple equation).
If I was setting up a lab and trying to save money I would use the g-ball instead of the traditional set-up (while still ‘learning’ the traditional set-up for exam purposes).
To order the g-ball contact the boys at ibotz.com
Oh. And did I mention that it’s fun?
Physics? Fun? Who’d a thunk?
By the way, this is the traditional method:
Think for Yourself 