It is mid-morning in the small town of Lenzie, on the outskirts of Glasgow, but science communicator Daniel Sansome is in full evening dress. With the aid of a tuning fork, a frequency generator, several musical instruments, a helium balloon, a plastic bat and a stream of willing helpers from the audience, he is conducting the Primary 3 class at Lenzie Moss School on a trip around the world of sound.

Kyle places his finger gingerly on a cymbal just after it has been struck. “I can feel it wobbling,” he says. “That’s what sound is,” Daniel explains, “little vibrations, little wobbles that go through the air to your ears.” But how essential, he wonders, is the air? Liam investigates by donning goggles and immersing his head in a bucket of water. After surfacing, he accepts the applause of his classmates and towels his hair. “It was loud,” he says.

“So that means sound travels through liquid as well as air,” says Daniel. With the assistance of a metal coat-hanger and two pieces of string, he shows that it also travels through solids. He talks about amplification, and demonstrates with a tuning fork and a small ukulele.

“That was about loud and soft. Now we want to think about high and low.” He uses a trapped ruler to show that rapid vibrations produce a high-pitched note. “Slow is low,” he summarises. “Fast is high. Now watch this loudspeaker. Can you see it moving and hear the hum? I’ll make it move faster.” He turns a knob. “It sounds like a car starting,” says Mithi.

“Now it’s a siren.”

The squeal ascends in pitch as he turns the knob further, until the children cover their ears in discomfort. A final turn and for most of the class the sound disappears. “Can anyone still hear it?” One or two hands go up. “You have good ears. Most people can’t hear anything if the vibrations are above 20,000 times a second, but dogs, bats and other animals can.”

Daniel is a musician and actor. When he talks about sounds that are soft or loud, high or low, his voice matches the words and,during a sequence on bat echo-location, it even acquires a Transylvanian accent.

For the grand finale he mobilises the entire class: the boys blow raspberries while the girls sing “la la la” at the tops of their voices. Liam hits a row of bottles with a hammer, Kyle plays the cymbals, Mithi the kazoo. Daniel belts out the melody on tenor saxophone and the teacher gives it big licks with a set of maracas. The effect is appalling, but nobody minds because this is science. Music will take a little longer.

Douglas Blane

To book Good Vibrations, aimed at Primary 3 to 7, tel: 0131 473 2070