Visible Light Waves
What are they?
All electromagnetic radiation is light, but we can only see a small portion of this radiation—the portion we call visible light. Cone-shaped cells in our eyes act as receivers tuned to the wavelengths in this narrow band of the spectrum. Other portions of the spectrum have wavelengths too large or too small and energetic for the biological limitations of our perception. As the full spectrum of visible light travels through a prism, the wavelengths separate into the colors of the rainbow because each color is a different wavelength. Violet has the shortest wavelength, at around 380 nanometers, and red has the longest wavelength, at around 700 nanometers.
How They're Made
Our eyes can detect only a tiny part of the electromagnetic spectrum, called visible light. This means that there's a great deal happening around us that we're simply not aware of, unless we have instruments to detect it. Light waves are given off by anything that's hot enough to glow. This is how light bulbs work - an electric current heats the lamp filament to around 3,000 degrees, and it glows white-hot. The surface of the Sun is around 5,600 degrees, and it gives off a great deal of light. Belive it or not, white light is actually made up of a whole range of colours, mixed together. We can see this if we pass white light through a glass prism - the violet light is bent ("refracted") more than the red, because it has a shorter wavelength and is slowed down more by the glass - and we see a rainbow of colours.This is called 'dispersion', and allows us to work out what stars are made of by looking at the mixture of wavelengths in the light.
Uses
Light waves can be made using a laser. This works differently to a light bulb, and produces coherent light, or light in which the electromagnetic waves maintain a fixed and predictable phase relationship with each other over a period of time. Lasers are used in Compact Disc & DVD players, where the light is reflected from the tiny pits in the disc, and the pattern is detected and translated into sound or data. Lasers are also used in laser printers, and in aircraft weapon aiming systems.
Dangers
Too much light can damage the retina in your eye. This can happen when you look at something very bright, such as the Sun. Although the damage can heal, if it's too bad it'll be permanent, and your eyesight will forever be impaired.
Future Possibilities
Regular LEDs can be turned into optical WLAN with only a few additional components thanks to visible light communication (in short, VLC). The lights are then not just lighting up, they also transfer data. They send films in HD quality to your iPhone or laptop, with no loss in quality, quickly and safely.
All electromagnetic radiation is light, but we can only see a small portion of this radiation—the portion we call visible light. Cone-shaped cells in our eyes act as receivers tuned to the wavelengths in this narrow band of the spectrum. Other portions of the spectrum have wavelengths too large or too small and energetic for the biological limitations of our perception. As the full spectrum of visible light travels through a prism, the wavelengths separate into the colors of the rainbow because each color is a different wavelength. Violet has the shortest wavelength, at around 380 nanometers, and red has the longest wavelength, at around 700 nanometers.
How They're Made
Our eyes can detect only a tiny part of the electromagnetic spectrum, called visible light. This means that there's a great deal happening around us that we're simply not aware of, unless we have instruments to detect it. Light waves are given off by anything that's hot enough to glow. This is how light bulbs work - an electric current heats the lamp filament to around 3,000 degrees, and it glows white-hot. The surface of the Sun is around 5,600 degrees, and it gives off a great deal of light. Belive it or not, white light is actually made up of a whole range of colours, mixed together. We can see this if we pass white light through a glass prism - the violet light is bent ("refracted") more than the red, because it has a shorter wavelength and is slowed down more by the glass - and we see a rainbow of colours.This is called 'dispersion', and allows us to work out what stars are made of by looking at the mixture of wavelengths in the light.
Uses
Light waves can be made using a laser. This works differently to a light bulb, and produces coherent light, or light in which the electromagnetic waves maintain a fixed and predictable phase relationship with each other over a period of time. Lasers are used in Compact Disc & DVD players, where the light is reflected from the tiny pits in the disc, and the pattern is detected and translated into sound or data. Lasers are also used in laser printers, and in aircraft weapon aiming systems.
Dangers
Too much light can damage the retina in your eye. This can happen when you look at something very bright, such as the Sun. Although the damage can heal, if it's too bad it'll be permanent, and your eyesight will forever be impaired.
Future Possibilities
Regular LEDs can be turned into optical WLAN with only a few additional components thanks to visible light communication (in short, VLC). The lights are then not just lighting up, they also transfer data. They send films in HD quality to your iPhone or laptop, with no loss in quality, quickly and safely.