This is a diffraction grating spectroscope. Point one end to a light source and the hold the other end to your eye. Your'll be able to see what colours the light source is made from. White light is made of a spectrum of light, from red at one end of the spectrum, to the violet at the other.
If you indirectly point it at the sun you see the full spectrum of colour. However point it at a different
light bulbs and you'll see why they don't appear to be a bright white. They have whole sections
of the spectrum missing !
This is very handy for chemists, astronomers and scientists because hot gasses pass different
signatures of light. Enabling them to identify gasses. It may also be interesting for
photographers and other professionals to ensure the correct lighting conditions.
Note: The image shows the two types of spectroscopes we sell. The smaller is the pocket version.
For more information on diffraction grating click here