“Any sufficiently advanced technology is indistinguishable from magic” is a phrase known as Clarke’s Third Law, put forward by the science fiction author Arthur C. Clarke in his book Profiles of the Future: An Inquiry into the Limits of the Possible. This “bewildering bean” is about as far from “advanced” technology as you can get but, to the unsuspecting observer, it genuinely looks like magic.

TOP TIP: I didn’t do this in the video, but colouring in the bean template before making it is another way to make this activity more fun and engaging for children. If you want to challenge yourself, you could try making some kind of tower of ramps for the bean to roll down.

If you can’t print off the template for any reason, you can simply copy its shape onto a piece of paper, just make sure that the width of the each of the three middle sections is a tiny bit bigger than the marble you’re using.

EXTRAS: The “bewildering bean” is, like many of the makes in Mr Shaha’s Marvellous Machines, a cheap and easy way to make a toy that can be bought from the shops, and works using the same principle. When I was a child, I’d heard of “Mexican Jumping Beans” which were beans which apparently moved around of their own accord. I never actually saw one of these myself, but found out much later that these “toys” were in fact seed pods containing the larva of a moth, which moved when warmed up, for example by holding in the palm of your hand, as shown in the video below:

MORE GOOD STUFF: Click here for more activities. I’ll be publishing more videos of activities from my book over the coming weeks. Check back here, follow me on Twitter or subscribe to my YouTube channel to make sure you don’t miss them.