Killing for Science: Sterilization with Gamma Radiation

As with most of my posts, this story begins with me and my curiosity.

We enjoy back scratches and long walks on the beach. I am so good at Photoshop. Wow. Just wow.

In the depths of the windowless labs that grad students such as myself call home, one will often find a number of things saying, "Sterilized with gamma radiation."

I'm having trouble actually finding one at the moment, so enjoy this blurry picture instead.

Being an eminent scientist of highest regard, I of course know what gamma radiation is. It is the highest energy, shortest wavelength of light (electromagnetic radiation).

Thank you, Victor Blacus of Wikipedia, for this nice image!

But the question remains, and has quietly niggled at the back of my mind, of how one creates such radiation in a controlled manner. In addition, how does one protect oneself from these Death Rays of Death(TM)? To answer these questions, I once again don my Internet armor and brave the wilds of Google!

Pretty much exactly like this.

Gamma radiation is generally produced in commercial settings by cobalt 60, an isotope of cobalt that is artificially created in ATOM SMASHERS (capitals used for dramatic effect). These Death Rays of Death(TM) are incredibly good at penetrating matter (are you thinking something dirty? Stop that. Shame on you), which is why they are great for sterilizing things, particularly things that are already packaged. When they actually do hit something, they whack electrons off of it. Inside of cells, that creates ions and radicals that go on to react with ans destroy everything else. Because the Death Rays are so good at getting through stuff, it takes a lot to keep them off you. You know how, at the dentist, they put that lead vest on you to take a tooth x-ray? Same concept, just a slightly bigger vest. Maybe like a foot thick.

Is that it, I imagine you asking? Well, some stories are short. Plus, I'm on vacation right now, so I'm shocked I actually finished this post before the new year! I wouldn't count on any more for a week or two, unless my co-blogger feels his spirit moved to write. Merry Holidays!



UPDATE: Super cool extra bit of awesome (that I forgot to add before):
According to my microbiology professor in undergrad, ground black pepper is chock-full of wee bits of insect and whatnot, because the producers can just sterilize it post-grinding. I've never actually tried it, but he said that you can see shiny pieces of beetle shell if you look at ground pepper under a microscope. Bon appetit!

How do you cool something?

I think we can all agree that refrigerators are made of magic. But, it may surprise you to know that there is also some science sprinkled in for funsies. Since I never got my letter from Hogwarts, I can't tell you about the first point, but I have journeyed far and wide (to the other side of the lab where the physicist--my co-blogger!--sits) to discover the secrets of

Let us begin with a quick refresher on thermodynamics. Hey, get back here! I swear it's not scary or hard. What it is is a great word to use to make your friends think you're smart. Look, we're just going to use this teensy equation, very harmless...

PV = nRT

where P is pressure, V is volume, T is temperature, n is number of molecules and R is the gas constant.

Super easy, right? Pressure, volume and temperature are proportional to each other! So, if we increase the pressure, either volume will decrease or temperature will increase--or, more likely, a little bit of both. Let's pop some numbers in there so you believe me. I'm going to ignore n and R for simplicity.

Let P = 5, V = 6, T = 30

P*V = T, therefore 5*6 = 30 (woo!)

Now, P = 6. Three options:

(1) V decreases to 5

(2) T increases to 36

(3) Mix of 1 and 2

What's that? You'd like a real world example? Alright, science fans, I whipped this one up just for you! Let us turn to our faithful friend, water.

Is that not just fabulous? Doesn't it make you feel good just looking at it?

As you know, if you take a room temperature pot of water and increase the temperature until it boils, it will turn to steam. Now, the temperature of the steam won't rise until all of the water evaporates (for reasons I will not get into because they aren't that interesting to most people). However, you will note that steam takes up a LOT more space than water does, which--oh my goodness here it comes--decreases the pressure.

Did you see what I did there?!

Why does it decrease the pressure? Because the molecules are farther apart! If you take a packed bus full of people and spread them out among 5 buses, those people feel less pressure on them from fellow bus-goers. Same deal with water and steam. Boom. We just proved that PV = nRT, the ideal gas equation, works in real life.

Now, armed with this thermodynamical knowledge, we are fully prepared to battle understand

If you have a refrigerator and you ever bothered to look at the back of it, you probably saw something like this:

What's going on there? I have made this very detailed, scientific, post-modern illustration to explain.

What a great invention. Science!

Pictures!

http://ndpa.org/wp-content/uploads/water-06.jpg

http://upload.wikimedia.org/wikipedia/commons/a/a7/ColorfulFireworks.png

http://images.dexknows.com/cms/images/How_to_Clean_Refrigerator_Coils_0.jpg