Graduated Student Tour

While letting myself into my lab a woman approached me and said, “Hi!”

She had just graduated UC Davis and was looking around all the buildings she hadn’t been in much.

She was a Landscape Architecture major (didn’t even know you could major in that). My building is for biological sciences, so its understandable that she had probably never set foot in it before.

My lab’s building, Briggs Hall, is interesting from an architecture perspective (but maybe not landscape architecture).

The building was built in 1971 when there were a lot of campus demonstrations (still are! Pepper Spray Cop was at UC Davis).

A method of cutting down on demonstrations was giving students no places to gather indoors. Thus Briggs Hall’s layout is amazing confusing and even I get lost in it after working in the building for several years.

Briggs also doesn’t have any staircases inside. All of the stairs are on the exterior of the building. Don’t ask me what lunatic decided that was a good idea for a four story building.

Anyways, the recently graduated student asked if there was anything interesting in Briggs.

I showed her my lab. She glanced around in it, but not being a biologist she didn’t really understand anything in the lab.

I showed her the -80°C (-112°F) freezer which she did like as summer is starting in Davis.
I also showed her my favorite part of Briggs, the back exit by the police station.
The back exit is where all the old equipment is put that no one wants anymore. These are the pieces that are too big to just throw in the trash.
There’s old computers, old centrifuges, old heating blocks, old incubators. Tons of cool science equipment.
It’s this sort of industrial wasteland and NO ONE EVER GOES THERE.
My lab is super peaceful, but if something ever got too stressful and I needed to go outside, this is where I’d go.
Why does industrial junk calm me down? I had an air filter going in my room constantly when I was a kid. That constant hum while I slept made me associate industrial hums and old appliances with peaceful rest.
So now places like this always calm me down.
Course, the graduated student didn’t get any of that business. Shook her hand and congratulated her on graduating after I showed her the junk pile before going back inside to my lab.

Liquid Nitrogen in the Lab

A thermos with some bubbling liquid nitrogen at the bottom.
A thermos with some bubbling liquid nitrogen at the bottom.

Liquid nitrogen is used pretty much everyday by someone in my lab.

Liquid nitrogen is an extremely cold liquid coming in at close to -200°C (-330°F).

Nitrogen’s natural phase is a gas. Its a fairly common gas to, making up 78% of the Earth’s air.

When it nitrogen is condensed as a liquid it is essentially always at boiling temperature.

I tried to capture the vapor coming off the bubbling liquid nitrogen in the picture above, but its difficult to convey what liquid nitrogen is like in a photo.

Liquid nitrogen looks exactly like boiling water. If you put liquid nitrogen into a pot it would look just like a boiling pot of water ready for spaghetti to be added.

But liquid nitrogen is not boiling water. It won’t scald your hand if you touch it.

Liquid nitrogen is the coldest thing you will ever touch and can instantly freeze burn your hand.

Even things that come out of liquid nitrogen are painful to touch with you hands. I can’t do it for more than a second.

Using gloves to handle liquid nitrogen has another problem attached to it.

When you wear gloves a natural layer of sweat and oil occurs between your hand and the inside of the glove.

If your gloved hand is in the liquid nitrogen for too long, the sweat freezes.

That’s just ice though. It’s happened to me plenty of times. I just yank my hand out of the nitrogen and my bodyheat melts the ice back into sweat right away.

So if its so dangerous, why do we use it in the lab?

Liquid nitrogen is useful because it stops all biological activity. That’s why its dangerous and why its useful at the same time.

When working with a dead specimen its best to prevent bacterial decay. Bacteria can’t survive at liquid nitrogen temperatures, so its used for that.

Liquid nitrogen is also used to isolate RNA from a specimen.

Every cell has RNA inside of it, but RNA is also what many viruses are made out of.

Cells quickly learn to distinguish RNA inside the cell as good and RNA outside of the cell as bad virus RNA.

Cells have defense mechanisms to destroy RNA called RNases.

RNases can’t work at liquid nitrogen temperatures though!

I was using liquid nitrogen for a third purpose today, just to quickly freeze some worms.

More on why I need to freeze worms another day!

-Mister Ed


The big autoclave at my work that can hold four trays worth of autoclave materials.
The big autoclave at my work that can hold four trays worth of autoclave materials.

I’ve mentioned autoclaves in my science posts in the past. Autoclaves are one of the basic sterilization tools in a lab.

The autoclave pictured above is one of the bigger ones around used by the people in my rice lab.

What is an autoclave? Basically a its a steam oven.

When scientists were first trying to sterilize stuff, boiling a solution on a stove was the easiest way.

But boiling has a problem.

Say you want to create a solution of 3 liters of water with 4 grams of salt per liter. You measure out 3 liters of water and you pour in 12 grams of salt.

But now you need to sterilize it. You put it on the stove to boil.

After it boils you measure the volume of your solution and now only 2.5 liters are left!

So the solution is sterile, but its no longer the concentration you wanted.

There are ways to work around this obviously by adding more water or less salt, but that gets tiresome.

Eventually a French scientist, Charles Chamberland, invented the autoclave to avoid this sort of problem.

The temperature inside an autoclave heats up to 121°C (250°F). This is a higher temperature than boiling.

Normally water would boil in an autoclave and you’d have the same problem, but heating isn’t the only thing an autoclave does.

The air pressure inside is about 20 times room pressure. This air pressure forces the liquids you place in an autoclave to stay liquid instead of evaporating into gas.

Thus the temperature can be raised to kill any bacteria, microbes, or other nasty things in your solution of salt water, but the solution does not changed its concentration.

The most interesting part for me is why the machine is called an autoclave.

Autoclave is a Greco-Latin word that means self-locking.

With a normal oven you can open it at 250°F (121°C) and you’ll be fine.

But what if that oven was full of 20 times the amount of steam that normally would be in there?

The steam would fly out of the oven and give you horrible burns if the autoclave was opened suddenly.

Thus it was very important for Chamberland to prevent that accident.

The autoclave cannot be opened until the steam has been condensed into water and removed from the machine. The bottom left of the picture on this blog shows the pipe where the hot water comes out of the autoclave.

That’s all for today!

-Mister Ed