Posts Tagged ‘light’

What You can Do to Help Stop Deforestation?

Sunday, November 22nd, 2009 by mac

deforestation

We all are aware of the harmful effects of deforestation and how down the years, future generations are going to bear the brunt of it.

This particular problem is serious because it lays the foundation for bigger issues. And, it is due to this particular fact that governments are trying to deal with this issue in a better way. But, a major test for all the governments, environmentalists and individuals is to realize and inculcate ways in which they can curtail deforestation.

When you actually dig deeper into the details to know the reasons of this particular issue, it becomes clear that man has no one to blame but to himself. In the last few decades, man never thought twice before chopping down a tree. Whether it was for fuel, space or the wood, a tree was the first victim of man’s greed. But, it is a fact that the industrial revolution was the first beginnings of deforestation in large doses. This brought about huge amounts of climate changes and brought about the degradation of the environment.

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Cyalume Light Sticks – How do they work?

Monday, July 20th, 2009 by Lalu

“LIGHT STICK GLOW IN THE DARK!”

Light (Glow) sticks have not only become  an essential item for tactical forces and outdoor enthusiasts around the world but also for  party and concerts staple since they were being invented around 25 years ago.

6inch_glow

Have you ever wondered how do the glow sticks work? Lightsticks do not require bulb nor batteries to operate!  While it may seem like supernatural magic, we are going to tell you the technology behind light sticks ( which actually is very simple!) in this entry.

breaking

A typical commercial light stick contains a Hydrogen Peroxide solution, a solution containing  a phenyl oxalate ester, and a fluorescent dye. Before you activate the light stick, two solutions are kept in separate chambers. The phenyl oxalate ester and dye solution fills most of the plastic stick itself. The hydrogen peroxide solution, called the activator, is contained in a small, fragile glass vial in the middle of the stick. When you bend the plastic stick, the glass vial snaps open, and the two solutions flow together. The chemicals immediately react to one another.

light-stick-diagram
Here’s the sequence of events when the two above solutions are combined:

1. Hydrogen peroxide oxidizes the phenyl oxalate ester, resulting in a chemical called phenol and an unstable peroxyacid ester.

2. The unstable peroxyacid ester decomposes, resulting in additional phenol and a cyclic peroxy compound.

3. The cyclic peroxy compound decomposes to carbon dioxide.

4. This decomposition releases energy to the dye.

5. Electrons in the dye atoms jump to a higher

level, then fall back down, releasing energy in the form of light.
This is how the light sticks produces light. The particular dye used in the chemical solution gives the light its distinctive color.

photon_wallpaper_8_800

If you want a brighter light to be emitted from the stick, you may heat it.  Heat energy will accelerate the reaction between the chemicals and the stick will glow brighter, but for a shorter amount of time. If you cool the light stick, the reaction will slow down, and the light will dim. So f you want to preserve your light stick for the next day, put it in the freezer. It will not stop the lighting process, but it will drag out the reaction considerably.

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