INTERNATIONAL DAY OF LIGHT
16 MAY

The International Astronomical Union Network for Astronomy School Education (IAU-NASE) will celebrate the International Day of Light by encouraging people worldwide to perform William Herschel’s historic experiment that turned out on the discovery of infrared light.

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Herschel’s experiment

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The infrared region of the electromagnetic spectrum was discovered by British astronomer William Herschel in 1800 using a prism and thermometers. He designed an experiment through which it is possible to obtain the visible spectrum, by passing white light of the Sun through a prism. Where the spectrum is displayed, 3 thermometers are placed, one in the blue region, another in the red one (both colors detectable by the eye) and the third thermometer beyond the red, immediately after. To show that something is happening with the thermometer that is beyond the visible limit of low energy of the spectrum (the red region), the room temperature is controlled with a fourth thermometer. By conducting this experiment, Herschel discovered that the temperature marked by the thermometer in that area was greater than that of the environment.

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Global Participation

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The IAU-NASE want to encourage students worldwide to repeat Herschel’s experiment to highlight the importance of parts of the electromagnetic spectrum other than visible.

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Once participants have made your measurements, you should send it to the NASE programme using the contacts below and all results will be shared globally.

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The guidelines to perform that experiment are available in English and Spanish.