Chlorine Talk: Oxidizers

So now that I've glanced over one of the most common applications of chlorine, I thought I'd provide a bit more information on the chemical nature of chlorine itself.

Chlorine is a part of a group of chemicals called oxidizers. Basically, this means that in a chemical reaction, chlorine pulls electrons off of surrounding elements, just like oxygen does in a fire. In fact, fire is nothing more than oxygen pulling electrons from fuel (like wood) when exposed to a heat source greater than the fuel's flash point, which is a term that refers to the temperature at which our fuel is no longer stable and becomes combustible. Charcoal has a high flash point, which is why lighter fluid (which has a low flash point) is used to heat the charcoal up to its own flash point and burn of its own accord, rather than with the support of the lighter fluid. A flame is the result of some of the heat (energy) from the combustion being transferred to the electrons that the oxygen pulled off the fuel. These electrons then release the energy in the form of light. 

So now we know what an oxidizer does and that oxygen is usually the oxidizer regarding fire. Chlorine can act as an oxidizer instead of oxygen. For example, hydrogen can burn in chlorine. The hydrogen acts as the fuel (and it's very good at this, just look at the Hindenburg), and the chlorine is the oxidizer. Incidentally, the result of this reaction  produces gaseous hydrogen chloride, also known as hydrochloric acid, which I shall discuss in further detail in another post.

As an oxidizer, chlorine is not flammable by itself, but it can cause other materials to combust. So if I were to hold a flame up to some pure chlorine, it would not ignite; however, if I held a flame up to some hair spray (outside of the can, of course) it would instantly combust (that's right, hair spray is quite flammable) which is why hair spray cans have flammability warnings on them.

Oxidizers are also important in explosives, which work in much the same way as fire does; instead of burning over a period of time, explosives release their energy all at once. 

Finally, oxidizers are one of the primary culprits behind corrosion. Oxidizers, again, usually oxygen, reacts with a metal, such as iron, to produce a salt and iron oxide, which is brittle and easily snapped. When a bit of metal oxides to much, it snaps, which can cause structures to collapse. This is what caused the silver bridge to collapse in 1967.

Chlorine Talk: Pools

A few posts ago, I mentioned that chlorine is toxic. I believe it is high time that that mentioning was expanded upon.

Chlorine is an atom found naturally throughout nature, usually a part of a larger molecule, like salt. It's also used heavily by man, in anything from corrosive agents, to disinfectants, and even weapons.

The one thing people think of most often when chlorine is mentioned is swimming pools. Chlorine is being used as a disinfectant to kill off bacteria and pathogens in this particular case. It does this by breaking down into hypochlorous acid and an hypochlorite ion. Both of these substances attack the lipids that hold cell walls together, resulting in the death of the cell. Imagine the cell as a tent, and the lipids as the poles that are holding that tent up. Once you remove those, the tent collapses. Luckily for us, our skin cells aren't quite as vulnerable to chlorine, even though it isn't exactly good for you. Oftentimes, chlorine is supplemented or replaced by chloramines, which kill off pathogens in almost exactly the same way, but are in a more stable form. This is seen as superior to pure chlorine (often called free chlorine) as free chlorine tends to evaporate before killing off much bacteria. As good as this sounds, chloramines are even more irritating to the human body than free chlorine is. Anybody who has gone swimming in a few different chlorine pools can tell that there are slight differences in the color of the water, the intensity of the smell, and how irritable the water is; these differences are due to difference amounts of chloramines being used by different pool owners.
My personal opinion is that chlorine pools don't necessarily need to be avoided, just be sure to shower afterward. Even diluted, chlorine and it's byproducts are pretty harsh chemicals. That's why your skin gets dry and your eyes red after a long swim.

 For those of you who own a swimming pool of your own, I recommend you switch to a copper ionizing system, which is often bundled together with a salt water system. A copper ionizing system works by running water from the pump between two copper plates that have a low electrical voltage running between them. This process is called electrolysis, it's the same thing that made the Statue of Liberty green (That's right, green wasn't the original color). That electrical current causes a small amount of copper ions to mix in the water. This copper is toxic to pathogens and algae, which keeps your pool clean. Don't worry, copper isn't toxic to humans or animals, not unless consumed at enormous levels that wouldn't ever be caused by the little bit of electrolysis that occurs in a pool system.

Salt water systems are often advertised as chlorine free filtration systems. This is completely untrue. As I mentioned before, chlorine is found naturally in salt. Salt water systems merely extract the chlorine needed from salt dissolved in the water. The salt merely acts as a sort of stabilizer, as the filter only takes as much as is needed to clean the pool. A salt water filter is better than a traditional chlorine system just because it only uses free chlorine without any chloramine added. The free chlorine levels found in a salt water pool are usually much lower than the concentrations in a traditional pool anyway. Without having a decent stabilizer (like salt) to keep the chlorine in the water, pool owners have to dump more chlorine in their pool to keep it clean.

Killer Cell Phones? Not.

According to a recent report by the World Health Organization (WHO), cell phones are a possible (note their use of the word possible) carcinogen, or cause of cancer. The WHO report states that radio and electromagnetic waves emitted by cell phones are a possible cause of brain cancer.

ELECTROMAGNETIC SPECTRUM

So first we need to know exactly what electromagnetic radiation is. Simple put, electromagnetic radiation is light. Not just visible light, mind you, but also radio waves, ultraviolet rays, infrared light, etc. First we'll need a bit of a description of light itself.
Light functions as either a wave or a particle; but for our current intents and purposes, we can just consider it to be a wave. A wave has two parts, frequency and wavelength, which are inversely proportional to each other according to the following equation f = c / λ.  f stands for the frequency, c is the speed of light in a vacuum (which is constant), and λ represents wavelength. This equation merely shows that as the wavelength gets bigger, frequency will decrease, and vice versa. now it's time for a diagram!

Right, so now some of you might be asking what all those numbers mean. The top section of the diagram is the wavelength/frequency. Frequency is how close together each oscillation is and wavelength is how tall. This picture doesn't show it, but as the frequency gets lower (further apart; I know, that means the number is getting higher. I didn't make up the system, don't judge me.) on the right side, the waves should be getting much taller (higher wavelength).The set of measurements below that wave are the wavelength measurements, in meters. So gamma rays are around 0.0001 nanometers (0.000000000039 inches). The rest of the graph just shows where each of our commonly used wavelengths are located on the electromagnetic spectrum, the bottom bit shows visible light.

ELECTROMAGNETIC RADIATION

Now a short segment on radiation. Radiation is defined by any set of energetic particles, energy, or waves traveling through a medium or space. This includes both light and sound, but usually just refers to visible and non-visible light. There are two types of radiation; ionizing and non-ionizing. Ionizing radiation is the stuff you always hear about on TV, the stuff emitted by nuclear waste that causes cancer. This type of radiation has enough power to remove electrons from cells, which can damage cells and DNA; when DNA is damaged enough like that, it causes cancer. Non-ionizing radiation is any radiation that doesn't have enough energy to change atoms; meaning that it is completely harmless. The only ionizing electromagnetic radiation is found on the short wavelength end of the scale, namely gamma rays, X-rays, and ultraviolet light. 

So now that we have an idea on what electromagnetic radiation is, what's causing it in cell phones, and why is it deadly? Any electronic device emits an electromagnetic field (EMF) as a result of the electrons flowing through it. There's nothing we can do about it short of putting our phones in a Faraday cage (which doesn't allow any electromagnetic signals to pass through it) which would negate the purpose of a cell phone. You may as well keep a rock in your pocket instead. Now that we know the cause, we need to know the effect. According to the WHO, cell phones are emitting an EMF on the microwave scale, same thing your countertop  microwave uses to heat up food. I'm sure most people reading this have been sunburned at least once. This was caused by electromagnetic radiation in the ultraviolet spectrum, emitted by the sun. But has anybody been sunburnt by any regular household light bulb? No, because they don't emit ultraviolet waves and visible light doesn't have a high enough frequency to be harmful. Microwaves(wavelength between 1 meter [3.28 feet] and 1 mm [0.039 inches], about the same as radio waves) and radio waves have an even lower frequency than visible light, they aren't ionizing. In fact, microwaves are technically a type of radio wave. The sun itself emits both microwave and radio radiation. I can't find any numbers on this radiation (it's apparently hard to measure what radiation is coming from the sun and what's coming from other sources), but I'm willing to guess that the giant ball of fire in the sky is emitting more microwaves and radio waves than your relatively puny cell phone.

I started talking about microwaves and bunched radio waves in there without explaining why. Radio waves are the wavelength used by cell phones to communicate with cell towers, satellites, etc. Now, I am no expert on this subject, so if concrete evidence contradicts my work, you should probably ditch that phone of yours. I'm just explaining how the WHO's hypothesis doesn't make scientific sense to me.