Think of a Number Series 4: Episode Guide & Ratings

The first of six programmes with Johnny Ball This week Johnny finds out about reproduction, discovering where your heart is and what your voice looks like. Also a machine that looks like us, but doesn't think like us and next generation robots that don't look like us, but think like us. Meanwhile - get around to generating an answer to this one - how many grooves are there on the average long-playing record ?

Johnny finds out how to measure a metre, what keeps a marching soldier in line when he puts his best foot forward and how a laser gets the measure when spying on a locked room. Meanwhile - how many times can you take accurately three from 333 ?

This week Johnny looks at a few musical numbers - discovering that time can change the National Anthem but still rule the waves. He also finds the key to play a violin, with no strings attached - what a fiddle!

Johnny discovers the secrets of Doctor Who's Tardis, a box that looks like one but isn't and a machine that makes boxes quicker than you can. Also there's a disappearing box, a multiplying box and a box that's bigger on the inside than it is on the outside. Meanwhile - box clever with this. Five balls in a box -can you give them all to five friends so one remains in the box ?

Find out how you can draw hyperbolas, parabolas and about the illusion that something is there when it isn't. So this week watch out for things that go with a swing, and for curves there's no place like cone.

Find out if a fruit machine is fair and how skittles are at the fair. Also see some of the latest electronic games including some that talk backl Meanwhile, see if you're game for this one: line up ten balls in a box so that there are an equal number along each side.