These are a lot of his favourite things

Thinking Aloud Cambridge Kettle's Yard

Richard Wentworth, best known as a sort of post-pop sculptor, probably couldn't devise a high-class art exhibition, but he's managed to give us an enjoyably unorthodox show in "Thinking Aloud" at Kettle's Yard, which tours to the Manchester Cornerhouse and the Camden Arts Centre next year. The exhibition seems to be aimed at clever young people in the 14-15 age bracket, and will be popular with schools. I hope the subsequent venues produce a helpful gallery guide.

There's something ineradicably boyish in Wentworth's approach, though he's now in his 50th year. Perhaps his exhibition is influenced by memories of a middle-class childhood in the 1950s. It's certainly not affected by art. Indeed, the atmosphere would be spoilt if Wentworth had included any superior or self-sufficient painting or sculpture. Instead, he has drawn on the collections of many museums to show us such things as a bird's nest, an original sketch for Disney's Pluto the Dog, a Scrabble game (you can play if you wish); and then an over-sized bicycle, lots of maps and plans for the Normandy D-Day landings, borrowed from the Imperial War Museum; plus a cardboard box full of toy dinosaurs, a Braille typewriter and much else. There isn't a stamp collection, but Wentworth does have the next best thing, Lisa Milroy's painting Stamps.

"Thinking Aloud" is one of the Hayward Gallery's National Touring Exhibitions, compilations which often add or drop certain exhibits as they travel round the country. Sometimes this makes a difference to a show, sometimes not. Wentworth's catalogue has a very long list of things that he plans to show us, yet none of them are absolutely essential to his enterprise. Maybe some items have been left behind at school or have got buried at the bottom of the dressing-up box. That's a pity, but there are always more objects to awaken our interest. For this is a collection of curiosities that could be endlessly extended and shuffled in all sorts of ways - depending on Wentworth's or the spectator's mood.

There is MacDonald Gill's original 1923 map of the London underground system, with Simon Patterson's amusing and popular reinterpretation of the poster based on the 1931 design by Henry C Beck, still in use; Joseph Paxton's first sketches for his Crystal Palace; drawings for the patent of a flip-top cigarette packet (1939); a skateboard; a model of an explosion, from a German toy-soldier set; a Romanian banner (courtesy of the Peasants' Museum, Bucharest); a drawing by Lloyd George; a body bag from the Hammersmith Hospital; artificial limbs; an antique rattle, made for scaring birds; electrical fitments; Alec Issigonis's design for the underside of his Mini (1956, and looking oddly like a Bomberg drawing); a mole trap, a mouse trap and a mortar and pestle.

I was intrigued by almost all such things, yet left without a feeling of satisfaction. Wentworth doesn't take us as far as an adult art-lover is entitled to wish. He's like an adolescent who has an intense interest in the world, yet in whom the aesthetic faculty is still unformed. An absence of artistic feeling is totally consonant with Wentworth's own sculpture. He makes things whose volumes and outlines are dependent on the example of serious sculptors, while failing to reproduce their genuine feeling for form. His pieces are interesting because of the outlandish, also demotic nature of his materials - chairs, tins and so on. "My studio is a mass of items," he says, and we believe him, "a bizarre landscape of abandoned forms".

Wentworth doesn't include his own work in "Thinking Aloud", so I say no more, except to observe that his sculptural ideas are borrowed from other people, just as this show depends on the most diverse loans. But what's his present game? One interpretation is that Wentworth has brought objects into an art gallery just to show that they have their own interest and that art isn't so special, whatever people might think. But he's not so dumb as to follow this familiar neo-Dada path. And he has no theoretical programme. Boys do not deal in theories. Nor do they have much knowledge of human relationships. Noticeably, not a thing at Kettle's Yard tells us anything about one person's emotions for another person.

The clue to "Thinking Aloud" is of course its title. We write silently, with luck thoughtfully, and on the whole people write to describe a single topic. When we think aloud, on the other hand, we merely say things that come into our heads, unbidden or unexamined. I suspect that Wentworth cannot write to explain himself. Without a doubt he can talk. The catalogue relies on snatches of his conversation, and recently he's been on two Radio 3 programmes, discoursing on things that happen to interest him, including condoms and vacuum cleaners, with light and entertaining eloquence.

Except that he makes one feel like a schoolmaster (an unusual experience for me). "Wentworth! What is the difference between a tool and an appliance? How many of the former are in your so-called art exhibition, and how many of the latter? Are you chewing gum, boy?" And a weird aspect of "Thinking Aloud" is that its spectator comes to resemble a teacher whose messages can never get through to a talented but idle pupil who is so absorbed in Hobbies Weekly that he has no time to spare for education. The Wentworth literature never mentions his school. Did he not enjoy school, so that he went to art college (Hornsey) rather than university?

On the matter of idleness: almost all of Wentworth's bits of machinery are antiquated or exhausted or broken. Fascinating though they are, they give an old-fashioned or useless air to the exhibition. In historical terms, the technology in the show on the whole ends at the time when Wentworth was growing up. There's one major exception, in his choice of photography. Wentworth has a better eye for camerawork than for any other form of art. In "Thinking Aloud" the photos are often images that we've seen before in the last few years, but they're still good.

Walker Evans we of course know, but can return to his American images time and again. Andreas Gursky's Atlanta (1996) is a marvel of technique, composition and laid-back social enquiry. Photographs by Bernd and Hilla Becher are always effective, though burnt-out German industrial plants do not lend themselves to the Bechers' poetry. I don't understand the point of Tim Head's State of the Art. He seems to have stacked up portable radios and vibrators so that his photograph resembles one of those night- time celebrations of Manhattan. Then he's added skulls and toys to the tableau. Surely Head has nothing against modern American womanhood, though it rather looks that way.

'Thinking Aloud': Cambridge Kettle's Yard (01223 352124), to 3 January (winter opening hours Tues-Sun 2-5.30pm).