Der Heliograph
Draw a picture with the rays of the sun
The ears work in a similar way to antennae, receiving sound from the outside. Enlarging the surface area of these living antennae results in increasing the intensity and changing the frequency spectrum captured and directed to the auditory canal. The larger the receiving area, the better we hear distant sounds. Check this phenomenon with your own ears in the open-air section of the exhibition. The same method was used by troops in anti-aircraft defence in WWI and partly in WWII to monitor enemy aircraft.
