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  • Some of the best moments of my life have happened in labs. Also some of the worst.

  • Like the time that I took a week to prepare a sample for NMR analysis,

  • and then a classmate washed out the vials while I was sleeping for the first time in 3 days.

  • Because he "couldn't find anything else" to use for his experiment.

  • Interestingly, that resulted in my personal most significant laboratory injury.

  • We all have one; I cut my hand while punching a paper towel dispenser in frustration.

  • No one ever brought it up again.

  • Today, we're going to talk about how to avoid injury in the lab,

  • and some good techniques for using laboratory equipment correctly.

  • First two lessons already learned:

  • never wash out a vial you aren't familiar with and don't punch paper towel dispensers.

  • [Theme Music]

  • Let's start with some very basic safety stuff; your hair.

  • If your hair is long, it shall always be up in the lab.

  • If it is not, it will catch on fire. I've seen it happen.

  • It can also knock stuff over, and occlude your vision, and droop into your flasks.

  • Same thing goes for anything that might hang off your body in the lab.

  • Droopy clothing, especially sleeves, are a total disaster.

  • Clothes should cover your body as much as possible; I like to go long-sleeve even.

  • Never, ever, ever, ever, ever wear sandals in a lab.

  • Long pants, closed-toed shoes, and socks; clothing that covers your entire torso. Always.

  • I'm sure you look hunky in your muscle shirts,

  • and I have nothing against exposed midriffs as a principle, but not in the lab.

  • Of course your eyes are your most vulnerable organ.

  • Always wear eye protection, and no, just glasses do not count.

  • And if you feel like your eyes are starting to tingle, or hurt,

  • or even if you don't know how something might have gotten in there, use the eye wash.

  • Because it never hurts to be careful, and, you know, we've all wondered what it feels like.

  • I've actually never done this, so this will be a new experience for me. Aaagh.

  • Gah! It does not feel particularly pleasant, but it's better than having your eyes burned out.

  • Do not eat or drink in the lab.

  • Despite our best efforts, stuff does sometimes get where we don't want it to be,

  • and if it gets in your food, or you accidentally pick up the wrong cup,

  • that's just a really embarrassing story for your obituary.

  • Also I would generally suggest avoiding working alone in a lab,

  • especially if you're working with any machinery or hazardous substances.

  • But it will be up to you and your advisers to make that decision when the time comes.

  • You may have seen this little symbol before, here.

  • It's the Hazardous Material or HazMat diamond, and it's got some useful information in it.

  • Each little box is rated 0 to 4. Zero being "no big deal," and four being HOLY MONKEY BE CAREFUL.

  • Blue is for health, the red is for flammability, and yellow is for chemical reactivity.

  • A 4 in health means certain kinds of exposure will kill you.

  • A 4 in fire is both very flammable and gaseous, so impossible to control outside of a closed container.

  • And a 4 in reactivity means that it is capable of exploding at room temperature.

  • The little area underneath is for any extra information like if it's radioactive,

  • or reacts violently with water or something.

  • If you ever need to know more about a chemical and what it might do to you or to the world,

  • there is the good 'ole MSDS, the material safety data sheet.

  • Every chemical has one, and it'll tell you all the terrible things that it might do to you.

  • If you ever need to find one really fast, you don't need to go to the cabinet anymore;

  • you can just Google 'MSDS HCl' or whatever chemical you think is in the process of killing your friend.

  • There will be information on how best to treat the person who got exposed.

  • Of course, you should have always read the MSDS before you even touch a chemical.

  • Also, you should probably assume that every liquid in a lab that is not water is flammable.

  • This baby here is a fume hood.

  • It sucks all the air in there out, so you don't have to breathe whatever is going on in there.

  • It's also why it's impossible to keep chemistry labs at the proper temperature,

  • because the A/C units and heating units are constantly pumping in controlled air,

  • and these are constantly sucking it out.

  • So if you're doing some chemistry that might contain some noxious fumes, that goes on in here.

  • And if you want it to work properly, first you gotta turn it in.

  • That's the vent and that's the blower. Now it is sucking air.

  • The second thing you want to do is make sure the sash is at the right level.

  • This has a little thing that tells you where the sash is supposed to go.

  • If you go above that, on this model, [machine buzzes] it'll buzz at you.

  • If the sash is higher than that, it's not gonna properly vent all the stuff to the outside;

  • some of it might get into your face and that would be bad.

  • As a side note here, if something happens to you in the lab and if you don't know whether it was serious or minor;

  • you're not sure, just tell your instructor.

  • I once inhaled a bit of nitric oxide which, though initially extremely unpleasant, seemed to subside after a while.

  • But it can have longer term effects: headache, nausea, disorientation, dizziness, pulmonary edema, death.

  • So I'm glad I fessed up, so that I could get taken care of.

  • Speaking of, if you want to know what something smells like, do not stick your face in it.

  • Waft, waft it toward your face.

  • Also never test something by tasting it, obviously. And never pipette by mouth.

  • I hear people say that and like who would,

  • but then I just found out that Heiko, the chemistry consultant for Crash Course,

  • has twice gotten HCl in his mouth by-from pipetting by mouth, which I will never forgive you for.

  • That is what these things are for.

  • You put that on the end there, and then you go one; you draw the liquid up with this thing.

  • That's what that's for! Also, these days, most pipetting is done by these guys, which are way cooler anyway.

  • Pipetting is one way to move a substance from one container to another, and it's a pretty good one.

  • But if you want to pour, you can pour, but let me just give you a tip: commit.

  • We tend to get all nervous when pouring stuff in the chemistry lab and go all slow with it, but that's terrible;

  • you won't overcome the surface tension and it'll dribble down the side of the container, so just commit!

  • At the beginning and at the end. Destroy that surface tension!

  • OK, back to safety.

  • The most common lab injuries are cuts and punctures,

  • and the most common source of those is cleaning up broken glass, which you should not do with your hands,

  • but with a broom and a dustpan, and then deposit the results into a bin specifically for sharp stuff.

  • But the worst thing, and it has happened so many times and it's so terrible,

  • is forcing a glass rod, or thermometer, or a piece of tubing through a stopper

  • and then it breaks and then right into and through your hand.

  • And it's -- you're in the hospital and you're in pain for the rest of your life, probably.

  • So when you're doing this, and it is sometimes necessary,

  • you can use a bit of water or lubricant or some kind of Vaseline to make it easier to go through,

  • and then you hold it close and make sure your hand is not on the other side.

  • So very close to make it go through like that; not like this, 'cause that's...no.

  • When you're done with an experiment, do not just dump the results into the sink,

  • unless this has been explicitly approved by the person in charge of chemical safety.

  • For some chemicals, like common acids or bases, dilution is the solution to pollution.

  • When they get diluted, all that's left is common ions like chloride ions from HCl or

  • sodium ions from sodium hydroxide,

  • in addition to some protons or hydroxide ions that are neutralized by buffer ions that are

  • present in your sewage system anyway.

  • Bottom line is they can be flushed with lots of water.

  • For other chemicals, flushing is not a good idea.

  • It probably won't hurt you, but it might hurt the environment.

  • Do put the products into an appropriate waste container, but not just any waste container.

  • Different solvents and reagents have to be disposed of differently,

  • and if you dump some stuff into the wrong container,

  • it can totally end up reacting with the other things that have been dumped in there. Not good.

  • Rule of thumb: always know the right way to dispose of something before you even start to use it.

  • This is an apron.

  • It protects you and your clothes just a bit extra

  • in case you're working with something hazardous like concentrated acids.

  • Aprons are nice because they're easy to get off if you spill something on them,

  • while if you're wearing pants, you might hesitate a bit too long before you ditch 'em.

  • Which reminds me: if you spill more than just a bit of anything super bad on your pants,

  • modesty goes out the window; just take them off.

  • Also, while you're taking them off, you might want to run over to this guy here.

  • His job is to dump a gigantic amount of water on you really fast.

  • Now usually you don't get to see these things in action unless there is an actual emergency,

  • but to thank you for sticking with us through this somewhat disjointed lecture on safety in the lab...

  • I'm gonna take this off. That's a lot of water! Aah!

  • Thank you for watching this episode of Crash Course Chemistry.

  • If you were listening, you learned what to wear in the lab, how to dispose of chemicals,

  • how to avoid the most common accidents in the laboratory,

  • how to pour properly, what the HazMat diamond is,

  • what an MSDS is, and how to use a fume hood.

  • This episode was written by me, our editor is Blake de Pastino.

  • Our chemistry consultant is Dr. Heiko Langner who is sitting right there laughing at me.

  • This episode was filmed at the environmental biogeochemistry lab at the University of Montana, so thank you to them.

  • It was filmed, edited, and directed by Nicholas Jenkins, our script supervisor was Dr. Heiko Langner.

  • Our sound designer is Michael Aranda, and our graphics team is Thought Café.

Some of the best moments of my life have happened in labs. Also some of the worst.

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實驗技術與安全:化學速成班#21 (Lab Techniques & Safety: Crash Course Chemistry #21)

  • 48 6
    Yrchinese 發佈於 2021 年 01 月 14 日
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