Name: 業餘實驗室的設備--第一部分 (Equipment for an amateur lab - Part 1)
Uploaded: 2021-01-14T06:44:18.000Z
Duration: 7 min 41 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

I’ve been asked by one of my patrons to go over the various pieces of equipment for setting up an amateur lab.

情態副詞

After thinking about it I realized i can’t possibly cover the whole thing in one video

because every lab is going to be different and the equipment needed for one lab might not be applicable to another lab.

So i’m going to split this video into a series and try and cover as much equipment as possible.

I’ll let you decide which ones are applicable to you.

In no particular order, let’s start with beakers.

Whenever people think of chemistry they most often think about beakers.

Used for handling and transferring chemicals as well as performing reactions,

their symbol as the defining tool of chemistry is rightly deserved.

Try and get an assortment of sizes for your lab and make sure the glass is a material called borosilicate glass.

Such glass has a low coefficient of thermal expansion and thus can withstand heat shock very well.

Another good thing about beakers is that you won’t confuse them with drinking glasses and possibly poison yourself.

Almost every serious chemistry lab has a hotplate stirrer.

It’s probably the number one piece of equipment you’ve seen me use in most of my videos.

As the name suggests, it behaves as a hotplate and allows you to heat up liquids.

But it also has a magnetic stirring function.

It works by having a magnet mounted on a motor underneath the hot plate.

The magnet couples to a magnetic stir bar through the hotplate and allows you to stir your solutions as long as you want without having to do it manually.

You of course need a supply of teflon coated stir bars that are chemically resistant

and you have to remember to retrieve them at the end of your experiments.

Unfortunately hotplate stirrers are ludicrously expensive.

The ones you see here cost hundreds of dollars each.

I’d say they were worth it if they were more reliable.

But the one you see on the left is broken and i don’t have the skill to repair it.

And the one on the right has had a heater element failure and a power supply failure that required replacement.

Neither of these hot plate stirrers lasted longer than a year.

So get a hot plate stirrer if you really want one, but be aware of the cost.

Some sort of weigh scale is absolutely essential for a laboratory.

In our particular universe the amount of a substance is directly proportional to its mass.

So measuring that is the most reliable way to know how much of something you have.

Now a laboratory scale like this one is very good, reliable, accurate and precise.

It’s also a few thousand dollars, so you’re probably not going to buy one, I sure haven’t.

Instead, most of your needs can be served by getting two scales of different ranges.

The reason why a good laboratory scale is so expensive is because it has a large dynamic range.

It can measure a wide range of values and also count tiny increments between those values.

That kind of precision requires good design and high quality machining that eventually translates to very high cost.

Instead, by using two different scales that have different ranges,

you can cover most of the measurements you’ll ever need.

Chances are if you’re measuring a heavy amount of substance, the small changes are inconsequential.

And if you’re measuring a very small amount of substance, you won’t be loading the scale with a heavy container.

So using two different scales can be very effective and cheap.

Each of my scales here are only twenty dollars each.

The drawback of this approach if you’re doing high precision analytical or semiconductor work

and need more dynamic range than your scale allows.

In those cases, using a less precise scale that can’t tell you what tiny amounts you have can seriously undermine your work.

Keep this in mind when selecting your scales for the type of work you’re doing.

Fortunately, for most amateurs, the two cheap scales approach is sufficient.

A very useful thing to have in an amateur lab is a large supply of resealable plastic bags.

For inorganic chemicals like salts, metals and so on, these are cheap and readily available storage.

A useful convenience is that they flatten or expand depending on how much they are filled unlike bottles.

So you can have a full bag of material and relatively unused bag and they’ll only take up as much space as needed.

Bottles and boxes however take up the same space whether they are full or not.

These bags are also a useful for safely storing bottled chemicals if you’re worried about leakage or vapors coming out.

So have a good supply of resealable plastic bags in your lab.

Just remember not to store organic chemicals or chemicals that dissolve plastics for obvious reasons.

A lab jack is one of those annoying things you don’t know you need until you need it.

And then you forget you need to acquire one when you don’t need it.

All they do is lift things to various heights.

While you can get away with just using anything on hand like other beakers.

A lab jack is so convenient and useful that i think it’s worth having one or two.

I primarily use these for sitting the receivers in my distillations.

Vials are tremendously useful for storing and running small reactions.

You’ve seen me use them in large number of my videos.

Vials have replaced the famous test tube for most chemists.

They’re self-standing so you don’t need a test tube rack.

They’re easy to stack and store and so many industries outside of chemistry also use vials so vials are pretty easy to acquire.

When buying vials pay attention to their caps.

Foil caps are good for non-reactive solids but will be destroyed by reactive acids or strong bases and they’re not liquid proof.

For liquids and more reactive substances like acids, plastic liners are prefered.

This one is a polycone type plastic liner. Now plastic is great but even plastic is permeable to organic solvents.

The ultimate liner is a PTFE or teflon liners.

You can use these for very wide range of chemicals and they’re extremely resistant.

They’re also rather expensive so keep in mind what kind of chemistry you’re doing and purchase the appropriate vials.

Now i’m not going to cover all the types of glassware in this video as that topic is so vast it requires its own video.

But what i do want to show you is the current standard of using ground glass joints.

Now in the past chemists had to connect glassware using corks.

Ground glass joints are the more expensive but ultimately more convenient modern way.

This is because the sizes have all been standardized and most glassware will be labelled with the right type of joint.

This one for example is 24/40 joint meaning it has 24mm wide opening that extends 40mm down.

The taper is standardized to 1:10 for all glassware.

I can mate this joint with any other piece of glassware of the right gender

even if they are from completely different manufacturers thanks to the standard.

Now 24/40 is a common standard for moderately sized glassware and for smaller glassware there is the 14/20 standard.

So pay attention to the joint sizes of the glassware you’re buying to make sure it’s compatible with your existing glassware.

That being said, having a mix of glassware is still very usable as there are adapters to fit different types of joints together.

This way you don’t have to purchase duplicates of every glassware part you have and you can mix and match parts for special experiments.

Now ground glass joints can seize up and become stuck.

To prevent this you first grease up the joints to both seal and lubricate them.

A very common grease is dow corning vacuum grease which is quite inert and in general won’t harm your reactions.

You can also use hardware store greases but be careful as some can react with your chemistry

or might decompose at the temperatures you’re working with.

Grease is conveniently applied by first putting some in a syringe and then applying it to the joint.

You don’t need to cover the whole thing, just a bit on the side

and turn the joints when you put them together until the lubrication gives an even coat.

Okay that’s all the time i have for this video. There is still a lot more to cover and more videos to go.

In the next video i’ll probably look at things like safety gear and stuff for electrochemistry.

If there is any piece of lab equipment you think i should go over, let me know in the comments.