No, it is not a child’s drawing of a trip to the circus. It is a preliminary sketch of Tate Modern’s latest installation, by the Brazilian artist Marepe.

His Victorian carousel garlanded with toffee apples and topped with a canopy made from rubbish will arrive in the gallery’s Turbine Hall a month after the wildly popular slides there at the moment are dismantled.

For critics of the world’s most popular museum of modern art, the two projects are evidence that Tate Modern has itself become a fairgound attraction. But yesterday the museum defended Marepe’s merry-go-round and Carsten Höller’s slides as “serious art”.

Catherine Wood, curator of contemporary art and performance at the Bankside gallery, said: “Both works might look like fairground rides but they function in a very different way if you are in a museum.”

Marepe’s installation is part of UBS Openings: The Long Weekend, the second annual arts festival at Tate Modern, which runs from Friday May 25 to Monday May 28.

Among the more conventional artworks appearing with it will be the winning self-portaits in a competition run in conjunction with The Times.

Open to anyone aged 11 to 18, The Tate Times Drawing Challenge will be judged by a panel including Grayson Perry, the Turner-prize winner and Times columnist, and Rachel Campbell-Johnston, chief art critic of The Times.

The best pictures will be exhibited throughout the Long Weekend.

The programme of events also includes a gigantic sound installation in the Turbine Hall, a giant boardgame for families, and a rare British performance by the New York prepunks, Throbbing Gristle.

On May 27, to mark the twentieth anniversary of Andy Warhol’s death, his first film, Sleep 1963, will be screened throughout the night accompanied by a recreation of the musical performance that inspired it. Gavin Bryars, Michael Nyman and Joshua Rifkin will all take turns to interpret John Cage’s historic 1963 staging of Erik Satie’s epic repetitive work for piano, Vexations 1893.

The night before, Marepe’s installation will be assembled by a team of artists working with “found” objects. “Marepe’s work is a poetic symbol and a sculpture as much as something to ride on,” said Ms Wood. “It is very serious. It’s about trying to create new images and experiences.”

David Lee, editor of the art magazine The Jackdaw, was not convinced: “What the Tate has proved beyond reasonable doubt is that if you turn art galleries into amusement arcades you will get a lot of people through the door.

“They kid themselves that they are getting a lot of people who are interested in art. They are not. They are getting a lot of people who are interested in fairgrounds.”

How to enter

— The Tate Times Drawing Challenge is open to anyone aged 11 to 18

— Self-portraits must be drawn with pen, pencil or fixed charcoal on A4 paper

— Click here or go to tate.org.uk/drawing for expert advice

— Closing date is April 14

— Entries to Tate Times Drawing Challenge, Communications Department, Tate, Millbank, London SW1P 4RG

— The judges include the artist Grayson Perry and the Times chief art critic Rachel Campbell-Johnston

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