# Forum for Science, Industry and Business

Search our Site:

## Measure the speed of light using Milky Way Stars®

27.01.2003

Nothing travels faster than light – it only takes 8 minutes for it to reach the Earth from the nearest star, the Sun, which is 150 million kilometres away. Now anyone can measure this speed – with chocolate stars and a microwave oven! The experiment is described on a new Institute of Physics web resource for teachers about fun physics demonstrations, inspired by the Physics on Stage 2 event.

Ian Cuthbert, Education Departmental Co-ordinator at the Institute of Physics, works out the speed of light using Milky Way Stars® and a microwave

The only equipment you need for this experiment is a microwave, a ruler and chocolate, cheese or any other food that melts. Remove the turntable from the microwave and replace with chocolate on a plate (so the plate does not rotate), and heat until it just starts to melt – about 20 seconds, depending on the power of the oven. There will be some melted hot spots and some cold solid spots in the chocolate. The distance between the hot spots is half the wavelength of the microwaves, and the frequency of the microwaves will be printed on the back of the oven. The speed of light is equal to the wavelength multiplied by the frequency of an electromagnetic wave (microwaves and visible light are both examples of electromagnetic waves). So from this simple experiment, and some easy maths, you can work out the speed of light from Milky Way Magic Stars®!

The resource describes this and many more wacky, weird and most of all fun physics demonstrations, which were presented at Physics on Stage 2, a Europe-wide teachers’ event held last spring in the Netherlands.

“Measuring the speed of light by melting chocolate is just one of hundreds of physics experiments you can do at home”, said Dr Kerry Parker, a teacher and co-author of the poster. “As UK representatives at Physics on Stage 2 we had such a rich experience that we wanted to share our favourite experiments with other teachers. By putting the information on the Web, the wonderful ideas will not be forgotten.”

Michelle Cain | alfa
Further information:
http://physicsonstage.co.uk

### More articles from Physics and Astronomy:

Hope to discover sure signs of life on Mars? New research says look for the element vanadium
22.09.2017 | University of Kansas

Calculating quietness
22.09.2017 | Forschungszentrum MATHEON ECMath

### Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

### Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

### Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

### Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

### Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige