US museum visitor caught out breaking sculpture

A US museum has shared a timely reminder not to touch their exhibits after a man was caught knocking a rare clock off a wall and breaking it.

The unidentified patron was visiting the National Watch and Clock Museum, in Columbia, Pennsylvania on Tuesday when curiosity got the better of him, NBC News reports.

A video posted online by the museum shows the man and a woman admiring the timepiece before they start touching it.

However, not content with just fiddling with the sculptural piece made by James Borden, the couple poke and pull at the clock.

When the man notices a pendulum he can't stop himself from giving it a swing and momentum gradually builds until moments later the clock crashes to the floor.

"This is why we beg visitors not to touch museum object" the caption on the Instagram video reads.

Museum Director Noel Poirier said he and other staff believe the destructive visitor was trying to set the clock in motion.

"Once he pulled it up a little too high, that weight came off track and the heavy weight came down, hit the clock, knocked the clock off the wall, so then you see the results," Mr Poirier said.

"I think what he was trying to do was raise the weight up because I think he thought that would make the clock run."

He added that the clock would not be on display for a few months but looked as if it was not beyond repair.