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2. These are used for TV and radio signals. The danger is that the wave lengths are different and could get mixed up and also can course cancer. These are used for for mobile phones and the danger is they can slowly cook your brain. These are use for remote controls. The danger for this is that they can cause skin burn due to heat. This is used for cameras and the danger for this it could be danger to your eyesight.

4. This can be used for detecting bank notes which could be forged. The danger for this could be severe sunburn or danger to cells. This is used for getting images of the body. The danger is they also damage cells and can cause cancer. These are used for killing cancer kills, but the danger could be that you could end up being killed if a ray is shine through your body since it damages all your cells and turns them into mush.

5. Everything we learn from stars is by looking at the light that comes from them, as we can not touch them or sample them. by observing this feature we can get some of the following information:- colours, brightness and also distance temperatures but we can not always find out everything about stars. The easiest thing to know about a star is how bright it looks.

6. Light may be polarised partially or completely in other words all of it or some of it. Light is polarised when it is reflected from a transparent material for example glass, the degree of polarisation will depend on the angle at which the light is reflected. The word polarized light means the way in which rays of light give different properties in different directions.

7. Polarised light has many uses, one of them are polarised sunglasses, these sunglasses block out a certain type of light from polarisation and a lot of light is blocked out. People wear sunglasses in hot weather when the suns out and glaring.

8. Laser light is different from normal light because it has a very tight beam and it is very strong and concentrated. Lasers are a special form of light, laser light does not exist in nature, that’s what makes it special, only human technology can create laser light. The light from a laser contains only one colour or wavelength rather than a lot of different wave lengths. Scientists say that laser light is ‘monochromatic’ meaning of one colour. They are many ways to produce laser light. They are lasers that operate with crystals. gas etc. Lasers can be small or large enough to fill an entire room, however they all have one thing to do is to generate more light by stimulating atoms with radiation that is light. Stimulating means to set it off to gain interest. Doctors can use lasers for eye surgery, Lasers can also carry TV and telephone signals over special cables. Metal workers use lasers to cut and weld metal into everything from street light poles to cars. Workers in clothes factories use lasers to cut through hundreds of layers of fabric at once.

9. The volcano on Krakatoa exploded in 1883, killing around 40,000 people, and covering the WORLD with ash. The Krakatoa volcanic explosion was the loudest sound ever heard in recorded history. It was heard almost 3,000 miles (approximately 4,828 kilometres) away.

10. At 0530, 16 July 1945, in a remote section of the Alamogordo Air Base, New Mexico, the first full scale test was made of the implosion type atomic fission bomb. For the first time in history there was a nuclear explosion. And what an explosion!

11. The town of Halifax (Nova Scotia, Canada) was destroyed by the explosion of a cargo ship loaded with military explosives. About two thousand people were killed and almost ten thousands were injured. Until the first nuclear blast, it was the largest man-made explosion in recorded history with an equivalent force of 2.9 kilotons of TNT.

12. As sound waves are used rather than radiation, the procedure is safe. Ultrasound scans are commonly used during pregnancy to produce images of the baby in the womb. Ultrasound scans can also be used to: detect heart problems examine other parts of the body such as the liver, kidneys and abdomen help guide a surgeon performing some types of biopsy. Ultra sounds are a very common thing now!

13. In military you can get hand held machines which can help the soldiers as they can fit in your back pack and way about six pounds much more convenient than a big massive machine. These are portable machines and can save the lives of soldiers.

14. Sound with a low frequency is called an infrasound. These are very low frequency sound waves and these can be given off by volcanoes and meteorite explosions. Infrasound is used by some big animals for communication for example whales can communicate over hundreds of miles using infrasound's. Infrasound waves hug the ground, travel for long distance without losing strength and are unstoppable, they are stations all around the world detecting low frequency sound waves. These infrasonic waves are sound waves so low in frequency that the human ear cannot detect them. Whales create pure vibrations that we cannot hear but our body and our senses experience them on many different levels, the whales are sending us very loving frequencies. Elephants and giraffes also use infrasound's to communicate between long herds which are over long distances. Infrasound's can also be used to detect volcanic eruptions, as a volcano erupts it produces infrasound which can be detected even if the volcano is in a remote area.