ALBUM INVISIBLE LIGHT

Academia Interamericana de Panamá

Cerro Viento

Science

Invisible Light

 

Teacher: Ramón Guerra

By: Michelle Alejandra Concepción

List # 9

Vo B

16-08-2010

INTRODUCTION

We tend to think of light as only the radiant energy that we see with our eyes. But the light we can detect with our eyes is a very tiny fraction of all the types of light that exist. Infrared light is one type of light that is invisible to us. Gamma rays, X-rays, ultraviolet light, microwaves and radio waves are other types of invisible light. All of these rays and waves are the same type of electromagnetic energy. They are different only because the length of their waves are different.

This work presents the concept of invisible light, spectrum and types of invisible light. Finally, a brief conclusion the subject.

INVISIBLE LIGHT

Maxwell's equations predicted invisible forms of light waves, like x-rays and radio waves.

Not only did Maxwell infer from his theory that light was a kind of electromagnetic wave, he also predicted that there were many other kinds of electromagnetic radiation, besides visible light.

Maxwell was right. In 1888, Heinrich Hertz discovered the existence of radio waves. This discovery led to an invention that has changed our world—the radio. However Hertz died aged 36, before Nikola Tesla and Guglielmo Marconi had realised this invention.

Radio waves are not the only other kind of electromagnetic wave. X-rays, microwaves, infra red, ultraviolet and gamma rays are all invisible forms of electromagnetic radiation.

We use many of these electromagnetic waves everyday. X-rays help doctors see inside our bodies, microwaves communicate between our mobile phones and satellites, and infra-red switches open our doors.

All of these kinds of waves are described by Maxwell's equations.

Around 1800—while Young was developing his wave theory—three scientists discovered that the color spectrum was bordered by invisible rays. Sir William Herschel, a British astronomer, was measuring the temperature of the colors dispersed by a prism. As he moved the thermometer down the spectrum from violet to red, he observed a rise in temperature. As he moved the thermometer

When Light passes through a prism, there are wavelengths kinger than the color red. We cannot see them. There are also wavelengths shorter than violet. We cannot see these wavelengths, either. Togeteher all these wavelengths of lightm the ones we see and the ones we cannot see, are called the electromagnetic spectrum.

Allthough we cannot see wavelengths longer than red or shorter than violet, we can detect them, and we can use them in many ways.


Types of Invisible Light

Ultraviolet: We know that the Sun is a source of ultraviolet (or UV) radiation, because it is the UV rays that cause our skin to burn! Stars and other "hot" objects in space emit UV radiation.

Radio Wave: Yes, this is the same kind of energy that radio stations emit into the air for your boom box to capture and turn into your favorite Mozart, Madonna, or Justin Timberlake tunes. But radio waves are also emitted by other things ... such as stars and gases in space. You may not be able to dance to what these objects emit, but you can use it to learn what they are made of.

Microwave: They will cook your popcorn in just a few minutes! Microwaves in space are used by astronomers to learn about the structure of nearby galaxies, and our own Milky Way!

Gama Rays: Radioactive materials (some natural and others made by man in things like nuclear power plants) can emit gamma-rays. Big particle accelerators that scientists use to help them understand what matter is made of can sometimes generate gamma-rays. But the biggest gamma-ray generator of all is the Universe! It makes gamma radiation in all kinds of ways.

X Rays: Your doctor uses them to look at your bones and your dentist to look at your teeth. Hot gases in the Universe also emit X-rays .

Infrared: Our skin emits infrared light, which is why we can be seen in the dark by someone using night vision goggles. In space, IR light maps the dust between stars.

CONCLUSION

Ligtn can be visible or invisible. You use invisible light in many ways each day.

Radar waves help forecasters tell us what the weather will be. X rays help dentists an doctors check for cavities and broken bones. Every time you turn on a radio or television, you are picking up invisible waves of light.

BIBLIOGRAPHY

1. http://astro.uchicago.edu/cara/about_cara/defn/irlight.html.

2. http://www.atsf.co.uk/ilight/

3. http://sci-toys.com/scitoys/scitoys/light/invisible/invisible.html

4. http://museumvictoria.com.au/scidiscovery/light/invisible.asp

5. http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.htm