Outside the school hall the Ochil Hills loom darkly impressive against a blue sky, with craggy Dumyat looking almost close enough to touch. But inside there is nothing more interesting than a few piles of bricks, scaffolding and pipework, and a couple of nondescript workmen, one tall and thin in a brown warehouse coat and flat cap, the other small, black-haired and clad in blue dungarees.
But the children trooping into the hall do not even glance at the spectacular view through the windows. They have seen it before and know its entertainment value to be limited. Hills are just scenery after all, but these two characters, one of whom is already, like many of the children, jiggling spontaneously to the music, look as if they might have potential.
They certainly do, and Menstrie Primary School is soon echoing to the delightful sound of children laughing uncontrol-lably, as builders Bill and Izzie carry them along on a tide of mime, slapstick and audience participation, all the way from Stone Age caves to Norman castles, concrete tower blocks and the surface of the moon.
Nicky McCabe and David Robertson are deft, agile and very funny. Their timing is marvellous to watch and the science of forces and gravity is well-integrated in the entertainment. The performers even have the courage o invite and capably answer children's questions after the show.
But holding the undivided attention of a hall full of children for an hour provides a priceless opportunity to tackle ideas that are central to a subject.
One of the most fertile discoveries in physics - that everything from a pin to a cannonball falls to earth in exactly the same way - is worth longer than just a few seconds.
And if the show spent more time on friction, which gives rise to stubborn misconceptions about how the world works, and less on pulleys, which are interesting but scientifically peripheral, it would become even more educationally valuable.
But although its content could be tweaked, the show's concept and execution are both brilliant. And, perhaps, the first scientist to explain forces, Galileo Galilei, whose work was dogged by conflict with religious authority, would have had an easier time if he had adopted the crowd-pleasing style of Bill and Izzie.
On the other hand, perhaps not. It is hard to imagine a member of the Inquisition seeing the funny side of being whacked on the head with a piece of lead pipe.
Push Off is aimed at the Energy and Forces attainment outcome of Science 5-14. It is designed for Primary 4 to 6 and Primary 7. EISF box office, tel 0131 555 6626.