|MadSci Network: Physics|
Its pretty hard to accurately measure the wavelength of light. The problem is that the wavelengths are very very small. The wavelength of visible light is about 1 millionth of a meter. In order to accurately measure the wavelength of visible light you need a sensitive tool called a spectrometer. With the help of a prism, you could roughly measure the wavelength of light being filtered out by the colored wrap. To do this, you'll first need to measure the spectrum of the original light source. Start by passing the light through a small vertical slit. You can make this out of cardboard by cutting a slit, say, 10 cm tall and 1/2 cm wide. Then pass the light from this slit through a prism. Shine the resulting 'rainbow' on a white piece of paper and carefully note the colors that are present (it would be helpful to do this in a very dark room). Then, do the same experiment, but place the filter between the light and the slit. Carefully note the color(s) that are missing. You can then use these rough numbers to determine the wavelengths that have been filtered out: violet: 400 nm (1 nm = 1 nanometer = 1 meter/1,000,000,000) blue: 500 nm green: 550 nm yellow: 600 nm red: 650 nm
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