Light phenomena demonstrations at Lichtjesavond

Every year on the second Tuesday of December, the city center of Delft changes into a Christmas market decorated with lights. The event is initiated by the lighting of the Christmas tree in the market square, an event named 'Lichtjesavond' or, loosely translated, 'Night of Lights'. During this event, a market stand was dedicated to show demonstrations of light phenomena to the general public, which was a collaboration of the Optics Research Cluster and the Optics Chapter Delft. A series of scientific demonstrations was presented, related to optics and light phenomena, aimed at children, parents, and general passersby.

Three demonstrations showed effects of polarization and scattering, linking these concepts to everyday life. For example, one demonstration showed how polarized light and birefringence can be used to inspect material stress in plastic objects. Another highlight was a thermal camera, which revealed that humans also emit light. This was demonstrated by overlaying a thermal image of a visitor's hand with a projector. Additionally, a near infrared camera with a monitor showcased how many everyday objects emit light invisible to the naked eye. This included LIDAR systems used in modern smartphones for features like FaceID and optimising focus by determining the distance of objects. The event also showed the wave nature of light, illustrated by holograms and a single slit experiment.

Furthermore, we used the opportunity to promote a photonics educational kit. The box contains a bunch of small experiments tailored for high school students and it was presented as outreach towards local high school teachers in physics or chemistry.

People from many backgrounds visited our demonstrations, for whom we highlighted the significance and interesting parts of light in our daily lives. This is the first time that the Optics Chapter Delft collaborated to host this event and will set an example for future editions of Night of Lights. Moreover, we built some of these demonstrations for the first time, and now we can add them to our inventory demonstrations for outreach, to be used in future events.

For more info on the student chapter, see: www.opticschapterdelft.nl