Cooking with solar energy

The Sun is the main energy source for the Earth and its rays can have surprisingly strong effects. Interesting Physics students could see it while experimenting with a parabola of 140 cm in diameter that is normally used for cooking in the open air. The parabolic mirror is made of aluminium segments of the total cross section of 1.5 sq meter and it can concentrate up to 1500 Watts of solar energy in its focus. We used this energy for burning a paper and cooking sausages in the Botanical garden of the Masaryk University. The last picture shows an experiment with concentrating sound waves with the mirror. Although it indeed transferred sound more efficiently between the teacher whispering in the focus and the students standing nearby, it turned out that it would be a bit non-practical as an interception device.