Two antennas

Exhibit on display in Stanislaw Lem Garden of Experiences, a branch of the Museum of Municipal Engineering in Krakow.

Description written by Paulina Kijak

To perform this experiment, two people stand in front of two parabolic antennas that are located 20 meters apart. Each antenna has a diameter of 190 cm. The experimenters stand one step in front of their antennas. Facing each other, with their backs to the antennas, they try to have a conversation. Next, they turn around and face the centre of their antennas and once again try to have a conversation.

It turns out that when facing the antennas, it’s entirely possible to have a conversation – even whispering. Sound waves that we generate during conversation bounce back from the surface of the antenna, whose parabolic shape additionally focuses them. If we place our ears at the point, where the sound waves converge, also known as the focal point, we hear the effectively amplified sound.

Listen to the audio description

anteny akustyczne