Glow Sticks – 1
Glow Sticks Since being invented some 25 years ago the glow sticks we as children have grown up with are still the partying craze at rave events and darkly illuminated venues that need that little kick of hand held lights. The principal on which glow sticks work to an everyday person is almost supernatural, but in fact the technology used to make it and the way it works is actually very simple indeed. But how does a light stick give off such a strong light source with no bulb and no battery. As a form of energy, light can be emitted through a variety of processes. These processes may include 1.
Incandescent lighting works through the emission of light due to heat, this is the process of an ordinary light bulb. 2. Both fluorescent and phosphorescent lighting is the emission of light in response to radiation energy. This can be directly related to a fluorescent light or more easily a television. 3. The final is the laser generation which is the concentrated emission of light using simulated emission an example would obviously be a recreational laser. All these processes work on the same basic principle: An outside source of energy excites atoms, causing them to release particles of light called photons.
When you burn something, for example, heat energy causes the atoms that make up the material to speed up. When the atoms speed up, they collide with each other with greater force. If the atoms are excited enough, the collisions will transfer energy to some of the atom’s electrons. When this happens, an electron will be temporarily boosted to a higher energy level also meaning it will travel further away from the atom’s nucleus. When it eventually falls back down to its original level closer to the nucleus, it releases some of its energy in the form of light photons.
A light stick does the same basic thing, but it uses a chemical reaction to excite the atoms in a material to cause light. We now realise that glow sticks encourage a chemical reaction which produces energy and in turn emits light. As many chemical reactions take place, the chemical reaction that places in a glow stick is set off by mixing multiple chemical compounds. Compounds are substances made up of atoms of different elements, bonded together in rigid structure. When you combine two or more compounds, the various atoms may rearrange themselves to form new compounds.
Depending on the nature of the compounds, this reaction will cause either a release of energy or absorption of energy. The process of chemiluminesence can be simply explained in the following. The reaction between the different compounds in a light stick causes a substantial release of energy. Just as in an incandescent light bulb the atoms in the materials are excited, causing electrons to rise to a higher energy level and then return to their normal levels. After the process whereby the electrons return to their normal levels, they release energy as light.
This is known as the process of chemiluminesence and is the reason why glow sticks work. But what are the chemicals compounds that react chemically in a light stick. In a typical commercial light stick there is a mixture of hydrogen peroxide solution and a solution containing a phenyl oxalate ester and a fluorescent dye. Here’s the sequence of events when the two solutions are combined: 1. The 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. The electrons in the dye atoms jump to a higher level, then fall back down, releasing energy in the form of light. The light stick itself is just a housing for the two solutions involved in the reaction — essentially, it is portable chemistry experiment. Next we’ll see how bending the light stick sets this experiment in motion.
But before the chemical reaction takes place the two chemical compounds are held separately. 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 tube located towards 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, and the atoms begin emitting light. The particular dye used in the chemical solution gives the light a distinctive color.
Depending on which compounds are used, the chemical reaction may go on for a few minutes or for many hours. If you heat the solutions, the extra energy will accelerate the reaction, 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. If you want to preserve your light stick for the next day, put it in the freezer it won’t stop the process, but it will drag out the reaction time of the two chemicals considerably.
