Had a debate with my cousin about whether microwaves cause cancer or not (she said yes, I said no). Unfortunately, she brought up terminology I never heard of before (specifically, primary and secondary radiation, and partial and chronic radiation) and I wasn't able to argue with her anymore because I didn't have the knowledge to call bullshit on the points she was making with those terms.
In preparation for next time I decided to look up those terms (no way am I going to lose a debate to someone who believes microwaves cause cancer), but unfortunately the only things I found were incredibly dense scientific literature that gave me more than I was asking for (what the hell are muons and mesons?), or vague things that didn't give me enough information (k, so secondary radiation is caused by particles emitting their own radiation due to interactions with primary radiation. What is the mechanism behind it then? Is a proton being ejected or is something else happening?).
What makes this situation such a wtf is that someone who is dumb enough to believe microwaves cause cancer has somehow become more knowledgeable about radiation than I am.
This isn't too impressive to be honest, but I'm not completely ignorant. If you can, please correct me where I'm wrong and point out things that I am missing.
Ionizing and Non-Ionizing Radiation
As far as the topic of microwaves causing cancer is concerned, this is really the only thing that matters. Ionizing radiation is forms of radiation that have enough energy to break the bonds in molecules and between atoms. Non-Ionizing radiation is radiation that doesn't have enough energy to do that. Ionizing radiation is the one that causes DNA damage (and therefore cancer) by breaking the bonds in DNA molecules causing all kinds of mutations to happen. Non-Ionizing radiation will never do that. No matter how much of it you are exposed to and for how long, the bonds in your DNA molecules will never be broken and cause cancer. If I placed you in a human sized microwave you would likely be cooked alive, but your DNA would be fine.
Electromagnetic Radiation
Electromagnetic Radiation, also known as light comes from photons. Photons are emitted whenever an electron in a high energy state moves to a lower energy state or ground state. The difference in energy between the higher energy level and lower energy level is the amount of energy the emitted photon will have. A photon's frequency is directly related to the amount of energy it has (more energy means higher frequency) and from the frequency one can calculate the wavelength (higher frequency, smaller wavelength). Ergo, more energy, smaller wavelength.
Microwaves are fucking massive. While most electromagnetic waves are measured in nano-meters, microwaves range in size from 1 millimeter to an entire meter. Just as a small wavelength is a signifier of a lot of energy, a large wavelength is a signifier of a small amount of energy. Microwaves are some of the weakest waves out there. They don't even have close to enough energy to be ionizing radiation. For reference, here is the list of all types of electromagnetic radiation from least energetic to most energetic. Radiowaves, Microwaves, infrared waves, visible light, ultraviolet, x-rays, gamma waves. Only the upper bound of utraviolet, x-rays, and gamma waves are ionizing radiation.
Particle Radiation
Particle radiation is what we typically think of when we think of radiation. It is the type of radiation emitted by radioactive elements such as uranium. According to Wikipedia there are 3 types of particle radiation. Unfortunately, I am only familiar with one of them and I'm not going to make a fool of myself by talking about things I don't already know (not till the first edit at least).
AlphaRadiation (α)
As you already know, an atom contains a nucleus filled with varying amounts of protons and neutrons. Some atoms contain too many protons and neutrons to be stable. When that happens, an atom (or isotope) is declared to be radioactive. Eventually at some truly random point in time, the radioactive atom will eject a proton in an attempt to become more stable. The flying proton then becomes an alpha-particle and it can collide with other atoms and molecules (such as your DNA) to wreak havoc.
beta radiation (β)
I've heard of this one before but at the time of writing this I do not know what it is in detail.
neutron radiation
This is something completely new to me that Wikipedia mentioned. I know nothing about this.
FAKE EDIT: So I decided to do further research on microwaves and cancer and I learned some new things. Apparently, it doesn't matter if microwaves count as ionizing radiation or not. You could zap your meal with high energy gamma rays and it would not kill you if you ate it. The only way to turn something permanently radioactive is by manually mixing in some radioactive isotopes (such as polonium nuclei). Despite the lack of a fear of radiation poisoning though, there are a number of reasons why you still don't do this (besides the fact that most microwave ovens leak a tiny amount of their radiation).
1. Power consumption. Smaller wavelengths have more energy in them, which means more electricity is required to produce them. 5 minutes of constantly emitting to gamma rays hurts your electricity bill a lot more than 5 minutes of constantly emitting microwaves. You may think that gamma rays might lead to a shorter cooking time which might off set the cost, but...
2. You won't cook the food thoroughly. If you've ever used a mobile phone indoors, you are likely aware of the fact that low-frequency radiowaves can pass through walls. Penetration is unfortunately a very complex topic when it comes to electromagnetic radiation, but as far as the subject of cooking is concerned the only thing you need to know is that microwaves pass through food too. Certain higher frequency wavelengths such as ultraviolet do not penetrate
food as well due to the properties of the materials the food is made from. From my limited research, it seems that gamma rays in particular are amazing at penetrating everything so they likely aren't affected by this caveat, but I will explain it anyway.
Microwave ovens do not actually heat food by directly zapping it with photons. Instead, they rely on a phenomenon called dielectric heating. To use a simple analogy, imagine a a row of compass needles next to a conveyor belt filled with magnets. As the first magnet approaches, the first needle rotates to face the magnet and follows it as it travels along the belt. Eventually the magnet gets too far away from the first needle to affect it, so the first needle rotates again to face the next magnet that is traveling along the belt while the next needle rotates to face the first magnet now that it's close enough. Repeat this until the movement of the needles generates enough kinetic energy to cook the entire meal.
Now for the more technical explanation. If you study advanced chemistry, you will know that polar molecules (such as water) have a charge. As an Electromagnetic wave oscillates, the polar molecules align themselves with the wave and follow it. Because the wave is constantly moving, the particles end up moving too and as a basic thermodynamics knowledge will tell you, kinetic energy equals heat! This is also why wet foods tend to turn out better when heated in a microwave, they are more susceptible to this effect.
So what's wrong with a wavelength that doesn't penetrate food well? In that case, what will happen is that the wave won't reach the inside of the food. To go back to the conveyor belt analogy, it would be comparable to there being a break somewhere along the way. Needles that are closer to the beginning of the conveyor belt still receive magnets so they produce heat, but not the ones further down since the magnets had at that point fallen off the belt. This ends up producing an effect similar to speeding up the cooking of a 10 minute meal at 450F, by increasing the oven temperature to 900F and waiting only 5 minutes.
3. Ionizing radiation changes the chemical formula of food. With the addition of high energy photons that are capable of ripping apart molecular bonds comes some complications. When molecules are broken in such a manner the fragments tend to have a habit of recombining. They do not always return to their original form though and you can end up with brand new compounds that weren't originally in your food. This will inevitably change the taste and you will lose a lot of nutrition as proteins and amino acids are broken apart and vitamins get destroyed. Perhaps if you had the perfect storm of components, you could accidentally create something lethal, but in that case it's more likely that whatever you zapped wasn't edible in the first place.
Despite all of these drawbacks though, people still use high frequency electromagnetic waves to treat objects. Medical tools are often sterilized by gamma rays, and despite what I said a moment ago, people still irradiate food (usually to preserve it).
FAKE EDIT2: WTF! I can't believe I stayed up till 5 AM to write that first edit. For the record, that means it took me 6 hours for me to do my research and compile this in this post. Anyway, I hope you enjoy. My cousin may still know more about radiation in general than me, but at least I'm now an expert on radiation and how it relates to microwaves.
EDIT 3:
Crap! A lot of the information here is a misrepresentation (A class 2B carcinogen basically means "we haven't researched this enough yet, it might be bad, it might be not"), but there are still some points that I need to cross examine (the link between magnetism and leukemia for example). I have a lot of work to do tomorrow.
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Topic: Things that made you go "WTF?" today o_O (Read 14958194 times)