Radio Dishes

Put your ear against the marked focal point. Can you hear the radio when the sound is captured by the other parabolic antenna?

Parabolic antennas can be used to detect very faint sounds from a long distance, sometimes as far away as from space. The radio playing music at a low volume in the exhibition is directed towards a parabolic antenna. The sound waves from the radio bounce (are reflected) off the antenna and are then transported in parallel through the air to the other antenna, where they are reflected in the same way and collect in the focal point of the other antenna.

The focal point is marked with an iron ring. Try putting your ear against it. Because the sound collects there, it is strengthened and is more audible at the focal point.

Parabolic antennas are used to capture and reinforce signals of various types, such as TV signals.