Chemistry Lab: Manipulation Of Glass Tubing

Summary

This video tutorial explains how to safely light and adjust a Bunsen burner, including manipulating glass tubing for laboratory use. It covers key steps such as checking gas control, adjusting the air intake for optimal flame, and ensuring safety. The tutorial also demonstrates how to properly heat and shape glass tubing by fire-polishing and bending it at 90 degrees. Safety tips like performing hose checks and cooling glass tubing are emphasized throughout. The video makes complex processes more accessible with a hands-on, step-by-step approach.

Takeaways

• 🔥 The Bunsen burner is used for heating materials in the laboratory by controlling the gas flow and air intake.
• 🔧 The needle valve stops gas from entering the burner until the gas control knob is loosened.
• 🔄 To adjust the flame, turn the gas control knob; 'Righty Tidy' closes the valve, 'Lefty Loosey' opens it.
• 💨 Adjusting the air intake controls the flame type; more air creates a 'whooshing flame of death,' and less air creates a luminous flame.
• ✔️ Safety checks include tugging the hose, ensuring the gas control knob is off, and adjusting the air hole before lighting the burner.
• 🔥 The nonluminous flame is efficient because it has a proper oxygen-to-fuel ratio and doesn’t produce glowing, unburnt fuel.
• ⚡ The hottest part of the flame is the light blue cone, used for high-temperature tasks.
• 🔧 Glass tubing can be cut and bent by scratching it with a file and using heat from the flame to manipulate it.
• 🔥 Fire polishing is used to smooth the rough edges of cut glass tubing by heating it evenly.
• 🧊 Cooling glass slowly after heating, called annealing, prevents it from cracking by allowing molecules to settle.

Q & A

What is a Bunsen burner and its primary use in the laboratory?

A Bunsen burner is a laboratory device used for heating substances. It operates by mixing gas with air to create a flame, which can be adjusted for different heating needs.

How does the gas control knob work on a Bunsen burner?

The gas control knob regulates the flow of gas. Turning it 'righty tighty' shuts off the gas, while 'lefty loosey' allows more gas to flow into the burner.

What is the function of the air intake in a Bunsen burner?

The air intake allows air to mix with the gas before it burns. Adjusting the air intake changes the type of flame, from nonluminous (blue, hotter) to luminous (yellow, cooler).

What safety checks should be performed before lighting a Bunsen burner?

1. Tug on the hose to ensure it is secure. 2. Make sure the gas control knob is off (righty tighty). 3. Ensure there is a small air hole open for gas to mix with air.

What is a 'nonluminous' flame, and why is it important?

A nonluminous flame is a blue flame that burns with a proper mix of gas and air, producing no light. It's important for achieving complete combustion and is used for most heating tasks in the lab.

What is the 'whooing flame of death,' and when is it used?

The 'whooing flame of death' refers to a flame with too much air, causing a loud sound. It is used to achieve high temperatures, especially at the tip of the inner blue cone, the hottest part of the flame.

How do you properly break glass tubing?

To break glass tubing, make a deep scratch on the surface using a file, then apply force with your thumbs directly behind the scratch to snap it cleanly.

What is fire polishing, and why is it done?

Fire polishing involves heating the rough edges of cut glass tubing in a flame until they are smooth and rounded. This prevents the glass from cracking and allows it to pass through rubber stoppers safely.

What is annealing in glass manipulation, and why is it important?

Annealing involves slowly cooling heated glass in a cooler flame to allow the molecules to relax, preventing the glass from cracking due to internal stress after bending or cutting.

Why is it recommended to turn off the Bunsen burner from the gas source and not the burner itself?

Turning off the burner from the source ensures that all gas burns out of the hose and burner, preventing gas from being trapped inside, which could be a safety hazard.

Outlines

00:00

🔥 Introduction to Using a Bunsen Burner

In this section, the speaker introduces the basics of using a Bunsen burner in a lab setting. They explain the components, including the gas source, needle valve, and gas control knob. Key safety tips are highlighted, such as ensuring the gas control knob is tightly shut ('righty-tighty') to prevent gas from escaping. The process of turning the burner on is detailed, focusing on the importance of allowing enough gas through the spud (orifice) for clean combustion. The role of the air intake and barrel in controlling the air-gas mixture is described, emphasizing the dangers of too much air, which can result in the 'whooshing flame of death'. Safety checks like tugging on hoses and ensuring the gas is off are also covered.

05:03

🔥 Lighting the Bunsen Burner and Flame Adjustments

This paragraph explains the proper technique for lighting the Bunsen burner. After completing safety checks, the speaker describes turning on the gas source and adjusting the gas control knob to sustain a flame. The difference between a non-luminous and luminous flame is introduced, with non-luminous being the preferred flame due to a proper oxygen-fuel balance. The speaker also explains how the luminous flame indicates incomplete combustion. The hottest part of the flame is identified as the tip of the inner blue cone, and the process of adjusting flame height using the gas control knob is outlined. Finally, the proper method for turning off the burner by shutting off the gas at the source is explained.

🔧 Cutting and Preparing Glass Tubing

The speaker moves on to explain how to manipulate glass tubing. They detail the process of measuring and cutting the glass using a file to create a scratch. Applying pressure at the scratch point allows the glass to break cleanly. The importance of fire-polishing the rough ends of the glass tube is discussed, with instructions on heating the glass in the flame until it glows, signifying it's hot enough. Fire-polishing helps create a rounded edge to avoid cracks, and the cooling process, known as annealing, ensures the glass molecules settle in a relaxed state to prevent breakage.

🌡️ Annealing and Bending Glass Tubing

This section focuses on the final steps of handling glass tubing, particularly bending and annealing it. The speaker emphasizes heating the glass evenly by rolling it in the flame and watching for a yellow glow, indicating proper heat distribution. They explain the technique for bending the glass at a 90-degree angle and the common mistake of getting a 'double bend.' Annealing is stressed as crucial to relieve the stress on the glass caused by bending, preventing it from cracking. The speaker reflects on their example bend, noting it is functional but not perfect. The tutorial concludes with a recap of the process and its applications for transporting gases.

Keywords

💡Bunsen Burner

A Bunsen burner is a piece of laboratory equipment used for heating, sterilization, and combustion. In the video, it's central to the demonstration, as the instructor explains how to light it, adjust the flame, and use it for various tasks such as manipulating glass tubing. The burner’s gas and air intake adjustments allow for control of the flame's temperature and type.

💡Needle Valve

The needle valve is a small component that regulates the flow of gas into the Bunsen burner. It ensures that the gas is controlled before mixing with air for combustion. The video describes how the needle valve stops gas from entering the burner until the gas control knob is loosened.

💡Gas Control Knob

The gas control knob is used to regulate the flow of gas into the Bunsen burner. By turning the knob (righty-tighty for off, lefty-loosey for on), the instructor shows how to control the gas flow to adjust the size and intensity of the flame. This knob is crucial for maintaining safe and effective use of the burner.

💡Air Intake

The air intake is the part of the Bunsen burner that allows air to mix with gas before combustion. By adjusting the air intake, you can control the amount of oxygen in the mix, which affects the type of flame produced. In the video, the instructor explains how more air produces a 'whooing flame of death,' which is a hotter and more efficient flame.

💡Luminous Flame

A luminous flame is a yellow, glowing flame produced when there is not enough air mixed with the gas, leading to incomplete combustion. In the video, this type of flame is described as ideal for tasks like annealing, which involves heating glass tubing. It’s contrasted with the non-luminous flame, which is more efficient but less visible.

💡Non-luminous Flame

A non-luminous flame is a blue flame that results from complete combustion due to a proper mix of gas and air. This flame is hotter and does not glow as brightly. The video emphasizes that this type of flame is ideal for general laboratory tasks requiring higher heat and a cleaner burn, such as heating glass.

💡Annealing

Annealing is a process where glass is heated and then slowly cooled to relieve internal stresses. In the video, this technique is demonstrated when the instructor bends heated glass tubing and then places it in the cooler flame to prevent cracking. It ensures that the glass is durable and safe to use.

💡Fire Polishing

Fire polishing involves heating the rough edges of cut glass tubing until they become smooth and rounded. The video demonstrates this technique after the glass tubing is broken, showing how to create a safe edge that can be inserted into a rubber stopper without causing injury or damage.

💡Spud (Orifice)

The spud, or orifice, is the small hole through which gas exits and mixes with air in the Bunsen burner before combustion. The video explains how the gas is directed through this tiny opening to create a controlled flame. This part is critical for ensuring that the burner operates properly and safely.

💡Glass Tubing

Glass tubing is used in laboratory settings for transferring gases or liquids between equipment. In the video, the instructor shows how to safely cut and manipulate glass tubing using the Bunsen burner. The process includes measuring, scratching, breaking, fire polishing, and bending the glass to create custom shapes.

Highlights

Introduction to Bunsen burner: explaining its purpose in the laboratory for heating substances.

Description of the Bunsen burner's gas flow: gas enters through the needle valve, controlled by the gas control knob.

Gas control knob usage: turning right (righty-tighty) shuts off the gas, and turning left (lefty-loosey) allows more gas flow.

Explanation of the air intake mechanism: air mixes with gas to ensure clean burning, adjustable via the barrel.

Safety checks before lighting: checking hose connections, ensuring the gas control knob is off, and adjusting the air intake.

Lighting the burner: instructions on turning on the gas and safely igniting the flame with a match.

Nonluminous flame: the ideal flame for most laboratory uses, indicating complete fuel combustion with proper oxygen mix.

Adjusting oxygen levels: increasing air intake creates the 'whooing flame of death,' a hotter, more efficient flame.

Demonstration of luminous flame: occurs when air is shut off, causing incomplete combustion, useful for specific applications like annealing.

Proper way to turn off the Bunsen burner: shut off gas from the source to prevent gas from staying trapped in the burner.

Glass tubing manipulation: step-by-step guide to measuring, scoring, and breaking glass tubing safely.

Fire polishing the glass: heating the rough ends of the glass tubing to round the edges, preventing cracks.

Annealing process: cooling heated glass tubing in a cooler flame to reduce internal stress and prevent cracking.

Checking if glass tubing is cool: using the back of the hand to detect residual heat before handling.

Bending glass tubing: heating the glass evenly in the light blue flame and gently shaping it to the desired angle.

Transcripts

hey guys today I'm going to show you how

to light a bunson burner how to properly

adjust it and also how to manipulate

glass tubing this is a bunson burner

it's used for heating things up in the

laboratory the source of gas comes in

right here travels along this tube where

it's stopped by a piece

called the needle valve these gaskets

prevent gas from actually entering the

burner until you loosen the gas control

knob the gas control knob is shut when

you turn it righty tidy and it won't go

anymore you don't have to go to turn it

off cuz you'll have to go to turn it

back on again nobody really wants that

so righty tidy is off Lefty Loosey let's

more in when you turn the gas control

knob on the gas comes through that tiny

little hole right in the center here

that tiny little hole is called the Spud

or orifice and it directs the gas

upwards in order order to burn cleanly

the air has to mix with the gas before

it burns so the air has to enter through

here the air intake the barrel adjusts

how much air is let in Lefty Lucy lets

more air in but this can cause the

whoosing flame of death barrel all the

way down barrel all the way down lets no

air in this is Oz the Great and terrible

before you light a burner there's a few

safety checks that you have to make

safety check number one tug on the ends

of the hose to make sure it's secure

just a light tug tug tug second make

sure that the gas control knob is off

righty tidy okay it won't go any further

that's good third safety check make sure

there's an air hole a little one is all

you need with these methane burners now

that the safety checks have been

completed turn the gas on from The

Source the gas is now coming through

this hose and is being stopped by the

needle

valve now light a

match then turn this gas control knob a

full half turn don't be shy you have to

let enough gas go through to sustain a

flame and the match can get placed into

the receptacle not in the sink you

notice how this flame isn't really

giving off much light this is called the

nonluminous flame because it's not

really generating any Flame a flame is

basically incompletely burned fuel

that's glowing because it's so hot well

because it's not glowing we know that

there isn't any incompletely burned fuel

there's a proper proportion of oxygen to

fuel what happens if I add more

oxygen this is called the whooing flame

of death there's more oxygen than the

fuel really needs to burn however we're

going to use the whooing flame of death

for a few things notice this lighter

color in inner cone right there at the

tip of the light blue cone that's the

hottest part of the flame we're going to

make use of that today if we turn the

barrel until the air hole is completely

gone we get a luminous flame this is

because since there is no air in here to

to mix with the gas the gas has to burn

with the air out here which it does

incompletely the incompletely burned gas

glows in the heat of the flame causing

this visible or luminous flame aluminous

flame is good for doing things like

annealing I'll show you that process and

know it has nothing to do with getting

on your knees on the floor or anything

for most things we want a nice luminous

flame to make the flame higher just

simply Lefty Lucy on the gas control

knob to make the flame lower righty tidy

on the gas control

knob to turn the burner off you turn it

off from the source not at the burner

this way you turn it off at the source

all this gas will burn out first you

turn it off here the gas will stay

trapped in here and won't burn

off and now to deal with the glass

tubing if you want to make glass tubing

to run through a rubber stopper and into

something else first thing you need to

do is measure out the length of the

piece of glass tubing that you need one

file's length is generally all you need

then place the file perpendicular to the

glass tube at a 90° angle cuz that's

what perpendicular means and then push

down and across once deep

scratch now we have a scratch on our

glass tube that's all you need to break

it the scratch is facing the camera my

thumbs are directly behind the scratch

together to put the most Force directly

into the scratch

push into the

scratch if it doesn't break right away

that's because your scratch isn't deep

enough so go back into your scratch and

just make it a little

deeper don't

saw again all the force directed into

the scratch from the other side of the

glass tube and it just falls apart it's

amazing now this end of the glass tube

is extremely rough so we're going to

need to fire polish it if we're going to

be able to put this through a rubber

stopper to fire polish it we're going to

heat it now as we heat it you're going

to see yellow flame that yellow comes

from sodium that's in the glass and

that's how we know the flame is getting

hot enough to do the job tug tug righty

tidy air hole we're ready to

go now I want a decent size

flame and I want a whooing flame of

death I'm going to heat the tip and just

the tip in the tip of the light BL blue

flame until it

glows rotating the glass tube to

maintain even

heating now we have a rounded Edge to

prevent it from cracking we're going to

cool it off slowly in the cooler

flame this is called ailing it allows

the molecules a chance to slide back

into a more relaxed position so that the

glass doesn't crack when it

cools then place the glass tube down on

a piece of wire gauze to cool while

waiting for it to cool place a wing tip

also known as a flame spreader on top of

the bunson burner you can't tell when

the glass tube is cool unless you put

the back of your hand over a top why the

back of your hand well the front of your

hand is kind of curved and it's not

terribly sensitive to heat the back of

your hand is actually more sensitive to

heat put the back of your hand over the

piece of glass tubing not on it just

over it if you still feel heat it's too

hot to touch mine is cooled down it's

now time to

continue when you put your glass tubing

in you have to be really careful you

notice how this flame is Hollow in the

middle you want to heat it on either

envelope of light blue flame if you heat

it in the middle it won't heat it all

roll the glass tubing in your fingers to

evenly heat it then look for the yellow

glow it's kind of like yellow snow

except completely

different once you get a yellow glow you

want to find The Sweet Spot the spot

where the glow is along the entire

length of the tube it will bend wherever

it's glowing if it only glows on the

ends you'll get a double Bend that's the

most common one mistake people

make when the glass gets all WGY you can

actually see it woing around pull the

two ends toward you

gently until you've got a

90°

Bend and then

immediately turn off the

air and anneal it in the cooler

Flame by bending it you're putting

stress on the long chain molecules that

make up glass the this will allow those

molecules to slide back into a more

relaxed

position and lay it

down to cool this piece of glass is okay

it's not a Great Bend I've got kind of a

double Bend in it it's bent a little

here and a little here uh it's not the

best Bend I've ever done uh but it's not

too bad it is

90° and it would definitely get the job

done transporting gases from one place

to another and that is how to light a

bunson burner how to play with a bunson

burner and how to manipulate glass

tubing