Another activity is designed for two people to play with emitting and detecting sounds from any of 12 overhead speakers.
United States officials, who have said no American submarines in the area were involved, have reported that underwater explosions were detected, sounds distinct from those of a collision.
One can detect contact, one detects sounds or music, one detects ambient light and the other distance from objects.
"As we map the sky, we can detect sound waves from the early history of the universe, more than 13 billion years ago," Benson said.
Sustained loud noises, as from machinery or music, as well as some drugs can damage the hair cells in the inner ear that detect sounds.
It can detect sound and visual cues from the children in their charge.
The rattle of a hansom sounded from an open space beyond.
Then, emerging from beyond the frequency at which human biology can detect sound, an indeterminate buzzing, perhaps of an insect, a rhythmic crunching, and a rustling like the uncurling of forest foliage.
Yet conventional hearing protection products also prevent them from detecting sounds that might indicate an imminent threat.
NASA's Chandra X-ray Observatory detected sound waves, for the first time, from a super-massive black hole.
A teen-ager poked his head out of yet another car and exclaimed wildly, "U.S. Embassy!" A muffled explosion sounded, coming from beyond the city.
