A chemical code.
Shown yesterday at 3.40pm on BBC1
A team of young adventurers set out to help endangered polar bears in the Canadian High Arctic.
The game show that tests friendships.
Monty mixes up the party invitations.
Aunt Mabel and Pippin go snail-spotting.
Why does Archie need to visit an optician?
Get Out. Will Michael and his disorganised family get to the church on time?
Repeats are not indicated.
10.30 See You, See Me (ages 9-11) 5329140 10.50 BBC Primary Geography (ages 7-11)
Archaeologists assess the remains of a chariot found buried with the tallest Iron Age woman ever found.
The Transformers. Tadpoles turn into frogs, caterpillars become beautiful butterflies: changing the body to suit the needs of a new lifestyle is one of nature's strangest tricks. Narrated by David Attenborough.
Repeats are not indicated.
1.00 What? Where? When? Why? (ages 6-7) Double bill.
The second round of the Grand Prix gets under way at Preston's Guild Hall. At this stage last year, Ronnie O'Sullivan made light work of Joe Swail , while Ian McCulloch - O'Sullivan's opponent in the final - had a narrow win over crowd favourite Jimmy White. With Ray Stubbs , Steve Davis and John Parrott. INTERACTIVE: digital viewers can view uninterrupted live coveraqe, action from other tables, plus news and statistics
The Grand Prix's second round continues. With
Steve Davis , John Parrott and Hazel Irvine. INTERACTIVE: digital viewers can access uninterrupted live coverage, action from other tables, plus a news and statistics service
4/6. London Calling. it's the end of the Second World War, and two London families tell of their contrasting experiences. Despite heavy bombing in the capital the Mitchell family lived an idyllic life, but just a few miles away the Moores tell a very different story.
Producer Grant Pollard ; Series producer Ian Cundall First shown on BBC1 Greater London Postponed from 27 September
5/8. Mull. Those twin curses of the great outdoors - midges and downpours - fail to dampen Bill's enthusiasm on the island of Mull, off Scotland's west coast. Here, he gets otter-watching tips from wildlife cameraman John Aitchison , takes an artistic view of seals, and hunts for treasure on the beach.
Producer Alex Griffiths ; Series producer Stephen Moss
The partnership of Rogers and Hammerstein, the history and culture of the Maya, rock group Queen, and the literary work of Lewis Carroll are the topics in this second-round heat. With John Humphrys. Director Derek Hallworth ; Series producer Pam Cavannagh
9/9. The Islamic World. From the palaces of Alhambra in Spain to Cairo's souks, Amani Zain explores the golden age of Islamic innovation. Adam Hart-Davis , meanwhile, enthuses over windmills and torpedos. Series producer Ian Potts (Revised repeat)
1/4. A 220-mile trek across Nicaragua, taking in mosquito-infested swamps, snake-filled rainforest and a tough volcano climb, would tax the fittest of explorers - and on this expedition, all 11 trekkers have a physical disability. How do you tackle dense jungle in a wheelchair? Cross a river if you're blind? Or warn a deaf man of hungry crocodiles? Teamwork is the key - but just 15 miles in from their starting point on the Atlantic Ocean's Mosquito Coast, there's an unexpected problem.
Beyond Boundaries 9.00pm BBC2
This series follows a team of volunteers as they take an arduous trek through the jungles of Nicaragua from the Atlantic to the Pacific. To complicate matters, each of the team has a physical disability. There are two wheelchair users, several amputees, one of the team is blind and another deaf.
It looks hellish: hauling wheelchairs through muddy jungle ravines when you're relying on a prosthetic leg is no-one's idea of fun. Soon, highly-strung Charlie, who is deaf, starts throwing hissy fits and winding up the rest of the team, who appear to work harder and complain less. It's a sour note, but you sense it's just the kind of tension the producers hoped to engineer.
Still, the extraordinary physical grit on show makes for inspiring television. David Butcher
New series 1/6. Culture-shock comedy starring Rob Brydon as a disillusioned astronomer who swaps his humdrum life in London for a job at an observatory in the Australian outback.
The Black Hole. Dr Paul Hamilton joins the observatory searching for adventure as well as black holes, but the first signs - oppressive heat, lethal wildlife and crazy locals - aren't encouraging.
Writer Harry Cripps ; Director Matt Lipsey ; Executive producers
David Maher , David Taylor , Beryl Vertue , Sue Vertue Brydon Down Under: page 17
Dr Paul Hamilton:
Dr Rachel Mann:
Professor Pip Cartwright:
Professor Mike French:
With Kirsty Wark. (5)
Places in the final 16 are up for grabs as the second-round matches continue. With Hazel Irvine.
Schools Repeats are not indicated.
2.00 Geography in Animation
4.00 Geography South Africa 2000