Measure Fraunhofer Lines
The sun produces all wavelengths of light. However, when you look at sunlight via a spectroscope there are some dark lines, which are absorption lines. These are called Fraunhofer lines, discovered by German Physicist Joseph Von Fraunhofer (1787 -1826), in his day they used diffraction gratings. Now with the 21st Century, things have gone high tech, so that now there are electrical devices called spectrophotometers that can measure multi wavelengths at once and produce data which can be represented in a graphical format. Even schools have access to these devices, like the Vernier Go Direct Spectrovis Plus Spectrophotometer.
In this experiment, you will
- Measure Spectral Absorption lines(Fraunhofer Lines) from the Sun using a Spectrometer. Label the major points against known reference values.
TIP: Ideally this needs to be done on a clear day for the best results
On the Go Direct® Spectrovis Plus, press the power button once. The Green Power LED will display and the Blue Bluetooth LED will blink. Launch the Spectral Analysis App. Click Connect a Spectrometer. Now select SpectroVis Plus in the list (if you have more than one device, select the serial number corresponding to that on the case). The Bluetooth Blue LED will now be constant. Click DONE.
Connect the Optical Fibre. Select Emissions V Wavelength. Press Collect
You can’t directly point the emission fibre at the Sun as there is a chance of causing permanent damage. So instead you need something to reflect the Sun’s ray. This can be as simple as a white piece of paper. Place the paper down on a flat surface so the sun covers the whole sheet. Hold the fibre at a 45° angle towards the paper.
Press stop. You can now analyse and compare the data.
You can now compare and discuss your data.
Does changing the material used to reflect the sunlight improve the results?
Why are there variances between the textbook values and values obtained?