how does radiation work and why is it dangerous?
In: Physics
Radiation is pretty much anything that is *radiated* away from a source. In common use it usually refers to one of two things:
Electromagnetic radiation. This is light, radio waves, x-rays, gamma rays, etc. All of this carries energy, so all of it can cook a person. The danger from being cooked by radiation is usually pretty small, but touching a live radio tower or getting hit by an extremely strong laser can cause burns.
Ionizing radiation. Some EM radiation can be ionizing, but not all of it. Ionizing radiation is radiation with enough energy in it that it can break electrons from atoms. This destroys molecules, so it breaks apart all of the microscopic machinery in your cells. It breaks apart tons of random bits in your cells. Some ionizing radiation stops at your skin and causes burn-like symptoms. That’s what a sunburn is. Other ionizing radiation like neutrons or gamma radiation can punch all the way through your body and cause more widespread damage.
Easiest way to think about is that it causes DNA damage, which interferes with a cells ability to make copies. Sometimes it screws it up to the point the cell dies immediately, sometimes at the time it divides, and sometimes it can cause damage that is mostly fixed. This imperfect repair is where mutations come from.
Radiation is usually just light, high energy light. At high enough energies, it can knock particles out of atoms, and lots of this can cause systems in your body to stop working. Like taking bricks out of a wall.
If those atoms happen to be in your DNA, it can cause the damaged cell to replicate wrong, making more damaged cells. Sometimes, these cells stop behaving as polite members of your body and divide/replicate forever, becoming cancer.
Sometimes radiation refers to actual particles shot out of nuclear reactions. Sometimes an electron (and a neutrino) are shot out, sometimes a whole helium atom (2 protons + 2 neutrons). This can also damage living things, but it isn’t stuff your body is likely to ever encounter. It’s important in nuclear fission/fusion.
Think of radiation as bullets from a really really tiny machine gun shooting super fast and all the time. These bullets are so small and are moving so fast that they shoot right through your entire body and barely slow down at all, and you don’t even feel them!
Unfortunately, they are also so small that they cut your DNA, which is basically the instructions that every cell in your body has to follow to do their jobs and make another cell
Cells are just about everything that makes up your body! You can take pretty much any part and if you look small enough, like with a really really good microscope, you’d see cells *everywhere*. You’ve got skin cells, bone cells, brain cells, even silly things like tongue and nose cells!
It’s really important for all these cells to work right because just like a car that has a lot of parts to it that all do different things to make a car move, all of your cells are a part of you and they each have a specific job to do, and usually part of their job is to make more cells to help them out!
That’s what DNA is for. It tells each and every cell what they do all day and night, and how to make other cells and give them the same instructions to do their jobs and make other cells too!
Ever try building a Lego set with only part of the instructions? Or worse, with completely mixed up or missing instructions? You might get it to look kinda like the picture, but a lot of the important stuff just doesn’t seem right. Somewhere in there you got messed up instructions, like when the tiny bullets messed up your DNA.
So when a cell has messed up instructions (DNA) telling them how to do their job and make other cells, they don’t do their job right, and they don’t even make other cells right!
So, when too many of your cells start doing the wrong things for their jobs, or are making bad cells, or don’t make other cells at all, your entire body stops working right. Like when one small part of a car stops working it might still drive but if too many things break, it needs to be fixed before it’ll drive again
When this happens, it’s called “radiation sickness”, and it is very dangerous, because before long your entire body forgets what it’s supposed to be doing to keep you alive, and you die. It’s a really scary thing that can happen if you’re exposed to too much radiation, but it’s okay because the dangerous kind of radiation is usually stored farrrr away from people and in very safe places where really smart people can keep an eye on it
Not all radiation is bad though, some radiation is very helpful! We use different forms of radiation to communicate, to power cities, or even to make our skin a slightly different color! Some types of radiation are more dangerous, but it’s usually easy to tell which ones should be avoided because there are lots of signs around where we keep them telling you to stay away just in case
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