INFRARED
Making invisible infrared radiation visible — The Earth's atmosphere consists mainly of nitrogen and oxygen. Greenhouse gases such as carbon dioxide and methane are only present in trace amounts, but still have a major impact! So what happens to the temperature of the atmosphere when humans release large amounts of CO2 into the atmosphere by burning fossil fuels? Pupils can explore this with the thermal imaging camera and understand the significance of the Earth's radiation budget and climate change.
Cola: the calorie bomb
How much sugar is hidden in our drinks? — We all know that candy contains a lot of sugar. But what is often overlooked is the unexpectedly high amount of sugar in our soft drinks. With the aid of hollow prisms placed in various liquids, we can measure how many sugar cubes are actually dissolved in a bottle of cola. The result is surprising!
3D vision
Building our own 3D cinema — Many movies are now shot in 3D. It is becoming standard that you receive not only a ticket, but also a pair of 3D glasses at the box office. But how are 3D effects produced, anyway? Using a simple structure, once can recreate this effect in the lab by taking advantage of different polarizations of light waves.
Transmitting data
There’s music in the laser! — Over the internet, screeds of data can be sent around the globe within a very short time. To experience how data is sent by means of light, students can transmit music from a smartphone via laser. When the laser beam hits the detector, the party gets started in the student lab!
Quantum Random
Generate real random numbers yourself. — This is possible with our quantum random number generator! Most random numbers used in encryption are calculated "pseudo-random numbers" and therefore not really random. However, with the help of quantum physics and single photons, real random numbers can be generated and checked for their randomness.
Mirage
How we can fool the senses! — Normally, light moves in a straight line. But under certain circumstances, light can travel in a curve, even without being encased in a glass fiber. Using a specially prepared sugar solution we can make a laser beam bend, and therefore understand why oases, which are not actually there, can sometimes appear in the desert.
Water as a conductor
We “lock up” light! — How is it possible that we can send light around the world using glass fibers? Why does light allow itself to be “imprisoned” in these fibers, and travel a curving path? In the student lab, we can illustrate this effect by capturing laser light in a jet of water and observing total reflection at work. Without any specialist tools, it can be understood that light does not always take the straight path.
The speed of light
Nothing in the universe is faster — In a single second, light can travel from the earth to the moon. Even to travel the huge distance from the sun to the earth, light needs less than 9 minutes – that’s for 150 million kilometers. Since light is very fast, but nonetheless has a limited speed, you can use it to rapidly measure positions. This is because at different distances, tiny time differences arise on light’s journey to various destinations. This we use not only for GPS, but also at our student lab!
Diffraction patterns
How can we measure the thickness of a hair without a microscope? — The Photonlab is a place where students regularly tear their hair out. Of course, they only do this to see who has the thickest hair. If you aim a laser on an individual hair, you can see a diffraction pattern projected on screen, where you can measure the hair’s thickness. You can see which hair color is winning the hair-thickness race on our hair honor roll.
Interferometer
Light + light = dark? — It’s surprising to see that when you fire two laser beams at the same point, it’s not twice as bright, but in fact, dark! With an interferometer, we can get on the trail of light waves – and even measure their size!
TASTY IN THE LIGHT
The experiment on color vision — The experiment "Tasty in the light" offers an excellent illustration of the connection between physics and physiology: color vision. Optical and physiological parameters are explained here and linked in an interdisciplinary way with biology, economics, philosophy and the pupils' everyday lives with the help of experiments they carry out themselves.
Laser speckles
Am I farsighted? — Lasers can be used to fix defective vision. But in our laboratory, it can also be used to reveal if you are shortsighted or farsighted. And all without needing to point a laser at your eyes: simply by analyzing slight movements of your head while you focus on a laser spot on a screen.
Spectral analysis
The colors of the rainbow — Our eyes can distinguish between different colors perfectly. But when several colors are overlaid in one spot, we can only see a mixed color. The sun, for example, emits a rainbow of colors, yet we see only white light. Using a spectrometer in the lab, we can reveal which colors are actually emitted from different sources.
Quantum cryptography
Encrypting your own messages! — Random digital keys are needed to encrypt messages in a tap-proof manner. These keys should only be known to the sender and the recipient - and preferably should not be able to be intercepted. In the student lab, you can try out how this works and send your own message. An interactive simulation on quantum cryptography can be accessed here.
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Polarimeter
Why soda manufacturers are interested in polarization — The polarization of light indicates the direction in which the electric field of a light wave oscillates. And as long as the light does not pass through special materials or filters, this direction remains unchanged. But if the light travels through a sugar solution, this polarization direction can rotate. This effect can be used to measure the sugar concentration of soda. You can also visualize polarization in the lab with birefringence using a calcite spatula or stress birefringence, the mechanical stress when an object is bent.
Welcome to Photonworld – a platform for knowledge, interesting facts and science on the topic of light. Photonworld aims to provide a basic understanding of the physics of light and its countless phenomena. From medicine, to art and physics: all topics are covered.
Photonworld originated as an initiative of the excellence cluster the Munich-Centre for Advanced Photonics (MAP) and the Laboratory for Attosecond Physics (LAP) at the Max Planck Institute of Quantum Optics (MPQ).
The initiator of the project is Prof. Dr. Ferenc Krausz, Chair of Experimental Physics at the LMU and Director of the MPQ.
Photonworld’s Student Zone reports directly out of the PhotonLab, which is supported by the Munich Center for Quantum Science and Technology (MCQST) and the DFG Research Unit FOR 2783. At the PhotonLab, schoolteachers and students can find up-to-date information about experiments and goings-on at the lab, and plan their own visit to the laboratory.
