Johnny Ball, with the help of a studio audience, will show some mind-stretching models, blistering ballistics, lightning calculations and some shocking ways to store your energy - and let it go.

This week Johnny discovers why hands are so handy, how to make sense of your senses, automate an automaton and how bionic a bionic man can be. Meanwhile - Think of a Number - How many times can you take 3 from 24 ?

This week Johnny looks at family trees, works out how to get rid of a boomerang, puts nylon in an endless spin and turns a fossil back into a dinosaur with the aid of an element that never forgets. Meanwhile - Think of a Number - a half is a third of it - what's the number ?

Lots of giggles and quite a few gurgles as Johnny explores water from H to O. Meanwhile - Think of a Number. At a quick guess, which set of numbers has the larger total ?

This time Johnny considers why the Earth is in a flat spin; talks about what makes tocks tick and how to gain on the swings and roundabouts. So meanwhile - Think of a Number - Divide 50 by a half and add three. What's the answer ?