Ultra-violet light waves


What are they?external image Visible-spectrum.jpg

Ultraviolet is the part of the electromagnetic spectrum, humans cannot see light of such short wavelength (or high frequency). Many animals such as some insects, some reptiles, crocodiles, salamanders, and small birds can see things that reflect this light.

The name 'ultraviolet' uses the ancient Latin ultra-, which means 'behind', 'beyond', or 'far'. Ultraviolet is beyond the visible violet light in terms of frequency, wavelength, and energy. Its wavelengths are between about 10 nanometers (nm) about 400 nanometres.

Are they dangerous?

Humans that live in places with more ultraviolet light have adapted by getting darker skins. Pigments absorb the ultraviolet radiation, so it does not get through the skin to kill or injure cells inside. Injury to the skin by ultraviolet is called "sunburn." When humans are exposed to too much UV light they can get skin cancer from the damaged cells.

How do we detect them?

You can use a filtrate, or a UV detector. The filtrate option is cheaper.


Where do they come from?

Powerful UV lights come from the sun, and man made things ( sun tan beds, UV lights)

What can they be used for?

They are used in tanning beds.

Use of tanning devices can cause skin cancer because ultraviolet goes through the skin and causes destruction to cells, causing sunburn.

Because of the destructive power of ultraviolet light, it can be used to kill germs. Sunlight is a powerful disinfectant

They are used in ultraviolet lights.

These lamps are often used to kill microbes (germs). They can be very powerful, so the people who work around them when they are turned on may need to wear protective glasses and keep their skin covered to avoid injury.


Anything else interesting?

The ozone layer around our Earth, prevents most of the UV light from the sun hitting us. Without this layer going outside would be very dangerous for us. Over places like Australia, the ozone layer has a hole in it due to global warming and greenhouse gasses, hence it is hotter and the sun rays are stronger so you are at risk to get burnt quicker.














How do different animals differ in the way that they see things?

Different animals have different kinds of color vision. Some have very poor color vision and others have very good color vision. In fact some birds and bees have super color vision and see colors that humans don't see.

Dogs, cats, mice, rats and rabbits have very poor color vision.

In fact, they see mostly greys and some blues and yellows.

external image vision2.JPG

external image jap-maple-pair-411691.jpg

How humans see things--------------------How dogs & cats see things



Does a red cape make them angry?

Does a red cape make them want to attack it?


Bulls are color-blind. They charge the red cape because it is moving, not because it is red.



For land animals, good color vision helps to tell the difference between ripe red fruit and unripe green fruit.


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In the table below, fill the cells with very brief notes. Use the other pages to gather the information from, and you may want to go outside of this wiki if you really can't find the information here (though I'd be surprised!).



Gamma
X-rays
UV
visible
IR
microwaves
radio
How are they generated?
radioactive atoms and nuclear explosions
X-ray tube, a vacuum tube that uses a high voltage to accelerate the electrons released by a hot cathode to a high speed, they can be produced many different ways to produce different frequencies of wave that can be used to see through different objects. They are produced in parcels of energy called photons. They are also produced naturally by many objects in the universe, scientists use these to work out what far away objects are.
Powerful UV lights come from the sun, and man made things ( sun tan beds, UV lights)
Everything with a temp above absolute 0
William Herschel conducted an experiment measuring the difference in temperature between the colours in the visible spectrum. He placed thermometers within each color of the visible spectrum. The results showed an increase in temperature from blue to red. When he noticed an even warmer temperature measurement just beyond the red end of the visible spectrum, Herschel had discovered infrared light!
Microwaves are essentially high frequency radio waves, which are made by different types of transmitter. For example, in a phone, they are generated by a transmitter chip and an antenna, while in a microwave oven they are generated by a 'magnetron'
Radio waves are energy waves that are generated by a transmitter. Radio waves are also known as electromagnetic radiation and the typical shape of the wave produced by a transmitter is that of a sine wave.
How are they detected?
Gamma-ray detectors contain densely packed crystal blocks. As gamma rays pass through, they collide with electrons in the crystal.
In hospitals the pictures are captured using image receptors such as thin films and photographic plates. Now they use computer technology to generate the images produced by X-Rays. Astronomers also use X-Rays, as these are absorbed by the earth's atmosphere they use balloons and satellites at very high altitudes. X-Rays can be indirectly sensed by humans but they cannot be seen by any human or animal eye.
You can use a filtrate, or a UV detector. The filtrate option is cheaper.
infrared camera

night vision goggles
Our eyes cannot see infrared waves but instruments that can sense infrared energy — such as night-vision goggles or infrared cameras–allow us to "see" the infrared waves emitting from warm objects such as humans and animals.
Radar uses microwave radiation to detect the range, speed, and other characteristics of remote objects. Development of radar was accelerated during World War II due to its great military utility. Now radar is widely used for applications such as air traffic control, weather forecasting, navigation of ships, and speed limit enforcement. Microwaves cannot be detected using human senses. Instead, there are devices for this. Microwaves are detected using devices called Geiger Tubes, which are gas-filled tubes that detect when radiation interacts with the gas inside the tubes
Antennas designed to detect radio waves are usually similar in size to the wavelength they want to detect. This is why many radio antennas have to be very long. If the antennas are not close to the size of the wavelength they do not usually do a good job of detecting the waves.
How might they be dangerous?
They are extremely harmful to living creatures
X- rays can damage cells and cause cause cell mutation which can cause cancer or cell death. It can cause these illnesses as it produces radiation as do lots of high frequency waves, this causes cells to behave differently and can have severe effects. Ironically X-Rays are also used to treat cancer, this treatment is called radiotherapy, it involves a very high amount of radio waves. People are X-Rayed fairly regularly and although the process is safer than it used to be there is still a relatively high risk of becoming ill as a side effect of the treatment.
Humans that live in places with more ultraviolet light have adapted by getting darker skins. Pigments absorb the ultraviolet radiation, so it does not get through the skin to kill or injure cells inside. Injury to the skin by ultraviolet is called "sunburn." When humans are exposed to too much UV light they can get skin cancer from the damaged cells.
Yes (Prolonged Exposure)
Damage/Kill
cells
Infrared waves are heat waves. If the cells absorb too much infrared radiation the heating will damage or kill the cells.
Infrared from the sun causes sunburn.
If you use them regularly, the fact that they are artificial, there has been growing concern that these waves can pose a significant health threat.Prolonged exposure to microwaves is known to cause "cataracts" in your eyes, which is a clouding of the lens, preventing you from seeing clearly (if at all!) So don't make a habit of pressing your face against the microwave oven door to see if your food's ready! Recent research indicates that microwaves from mobile phones can affect parts of your brain - after all, you're holding the transmitter right by your head. Other research is inconclusive, although there is a feeling that you're more vulnerable if you're young and your brain is still growing. So the advice is to keep calls short.People who work on aircraft carrier decks wear special suits which reflect microwaves, to avoid being "cooked" by the powerful radar units in modern military planes.
radio waves are not dangerous because they have a low frequency. Large doses of radio waves are believed to cause cancer, leukaemia and other disorders. Some people claim that the very low frequency field from overhead power cables near their homes has affected their health.
What are the main or most significant uses?
They are used to destroy cancerous cells. Doctors use gamma-ray imaging to see inside your body.
X- rays can be used to look at the internal structure of objects, they are often used in airport scanners as they can travel through fairly thick objects without being scattered or absorbed. This makes them very good at producing normally images of normally opaque objects, they can also be used to check for weak spots in metals. The idea of using X-Rays to see through human tissue was first formulated in 1895 in Germany. Dentists use them very often to get a more detailed image of the inside of the mouth, they can check for any chips or cavities much more easily than looking manually,especially right at the back of the mouth.
They are used in tanning beds.
Use of tanning devices can cause skin cancer because ultraviolet goes through the skin and causes destruction to cells, causing sunburn.
Because of the destructive power of ultraviolet light, it can be used to kill germs. Sunlight is a powerful disinfectant
They are used in ultraviolet lights.
These lamps are often used to kill microbes (germs). They can be very powerful, so the people who work around them when they are turned on may need to wear protective glasses and keep their skin covered to avoid injury.
Remote control
Some grills/ toasters
seeing in dark
Night vision goggles pick up the infrared light emitted by our skin and objects with heat.
-A remote control uses light waves just beyond the visible spectrum of light—to change channels on your TV.
-Infrared is also used for cooking in grills and toasters.
The can be used for Microwave ovens to cook food, they are used in mobile phones to send and recieve waves and satelite communication. Microwaves have wavelengths that can be measured in centimeters. The longer microwaves, those closer to a foot in length, are the waves which heat our food in a microwave oven. They are useful for transmitting information from satelites to earth, vice versa as microwave energy can penetrate haze, light rain and snow, clouds, and smoke. Smaller microwaves are used in remote sensing. These microwaves are used for radar. For example, the doppler radar used in weather forecasts. Microwaves, used for radar, are only afew inches long.
They broadcast radio and television, communicate with satellites, let mobile phones communicate with each other, make radar systems, and allow computers to share information without wires.

Good work. The UV section is formatted very well and has good material. The table is comprehensive, but rather over-full - as it needs to be memorable!
B+

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