Learning Objective

In this lesson we will learn about the different parts of a Bunsen burner, and how to use a Bunsen burner correctly and safely in a science laboratory.

Learning Outcomes

By the end of this lesson you will be able to:

  • Identify the different parts of a Bunsen burner.

  • Describe the different Bunsen burner flames and explain when each should be used.

  • Describe the steps involved in the safe operation of a Bunsen burner.

 

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Introduction

  • The Bunsen burner is probably one of the first things you think of when you think of a science laboratory.
    Although you won’t use one every day, you will often use them when you need to heat something during a practical experiment.
    Before you can use a Bunsen burner, you need to know a little about them so that you can use them correctly and safely in the laboratory.
    We’ll start off by naming the main parts.

 
Robert Bunsen burner

Although he didn’t invent the Bunsen burner, Robert Bunsen made important modifications to pre-existing designs, which lead to it being named after him.

(Image: Unknown, Wikimedia Commons)

 

The Barrel

  • The barrel is the main upright part of the Bunsen burner and the part where the flames comes out.
  • Never touch the barrel as it can get very hot while in use and can stay hot long after it has stopped being used.

 
Bunsen burner barrel

 

The Base

  • The base of the Bunsen burner provides the support for it to stand up.
  • It is also the safest part of the Bunsen burner to touch if you need to move or carry it, as it is designed not to get hot.

 
Bunsen burner base

 

The Air Hole

  • The air hole towards the bottom of the barrel allows air to enter the Bunsen burner, where it mixes with the gas.
  • The air hole can be partially or completely covered by turning the collar.

 
Bunsen burner air hole

 

The Collar

  • The collar is an adjustable metal ring that allows the air hole to be partially or completely covered.
  • This controls how much oxygen can enter the Bunsen burner, and therefore how much oxygen can mix with the gas.
    The more oxygen that is allowed to enter the Bunsen burner, the hotter the flame will be.
  • Always light the Bunsen burner with the air holes completely covered by the collar.

 
Bunsen burner collar

 

The Gas Inlet and Rubber Hose

  • The gas inlet is where the gas enters the Bunsen burner and mixes with the oxygen.
  • The gas inlet has a short length of rubber hose attached to it.
    The rubber hose connects the Bunsen burner with the gas tap on your lab bench.

 
Bunsen burner gas inlet rubber hose

 

The Bunsen Burner Flame

  • There are two main types of flame produced by a Bunsen burner – the yellow flame and the blue flame.

 

The Yellow Flame

  • The first type of flame produced by a Bunsen burner is the yellow flame, also known as the safety flame.
  • This flame is bright yellow and highly visible.
  • A Bunsen burner flame will burn yellow when the air hole is completely covered by the collar.
    Since you always light a Bunsen burner with the air holes covered, the flame will initially be yellow.
  • A yellow flame is the least hot Bunsen flame.
    Because the air hole is covered, less oxygen can burn with the gas, meaning the flame will not burn as efficiently.
  • Once the Bunsen burner has been lit, it should remain with the yellow flame until you are ready to heat something.
    Leaving the flame is ‘safety mode’ means that:
    1. You are much less likely to accidentally put your hand or other object in the flame because it is bright yellow it therefore very easy to see.
    2. Any accidental burn would be less severe as the flame is the least hot.
  • Never use the yellow flame to heat something.
    Heating with a yellow flame will cause glassware and other equipment to get covered in black soot, which is very difficult to remove.
    Also, since the flame is not as hot, it will take much longer to heat something.

 
yellow Bunsen burner flame

The yellow Bunsen burner flame

(Image: Milesl, Pixabay)

 

The Blue Flame

  • The second type of flame produced by a Bunsen burner is the blue flame, also known as the heating flame.
  • This flame is light blue and not easy to see, especially in a brightly lit laboratory.
  • A Bunsen burner flame will burn blue when the air hole is completely uncovered by the collar.
  • A blue flame is the hottest Bunsen flame.
    Because the air hole is uncovered, more oxygen can burn with the gas, meaning the flame will burn more efficiently.
  • There are two parts to a blue flame – the smaller, brighter section at the bottom, and the larger, less bright section above.
    The hottest part of the blue flame is the tip of the smaller, brighter section.
    Whenever you heat something, such as a piece of magnesium ribbon or a test tube, always hold it at this hottest point.
  • Only use the blue flame when you are heating something; at all other times return the Bunsen burner to a yellow flame.
    Since the blue flame is more difficult to see and much hotter than the yellow flame, you need to be very safety-conscious when using it.

 
blue Bunsen burner flame

The blue Bunsen burner flame

(Image: Swn, Wikimedia Commons)

 

Procedure for Lighting a Bunsen Burner

  • The procedure below should be followed each and every time you use a Bunsen burner.
    1. Put on your safety goggles and lab apron. If you have long hair, make sure it is tied back.
    2. Collect your Bunsen burner.
    3. Connect the rubber hose to a gas tap.
    4. Place a heat mat under the Bunsen burner.
    5. Turn the collar so that the air hole is covered.
    6. Light a match and hold it about 3 cm above the top of the barrel.
    7. Turn the gas tap to the ‘on’ position.
    8. Once the Bunsen burner is lit, extinguish the match.
    9. Leave the Bunsen burner flame in ‘safety mode’ until you need to heat something.

 
lighting Bunsen burner

(Image: Swn, Wikimedia Commons)

 

Safety Rules when Using a Bunsen Burner

  • Although it is fun to do scientific experiments that involve using a Bunsen burner, it can potentially be very dangerous if not used correctly and safely.
    Therefore, in addition to the general laboratory safety rules, there are several very important safety rules specific to using a Bunsen burner that you need to be familiar with.
    • Always wear safety goggles and a lab apron when using a Bunsen burner.
    • If you have long hair, always tie it back when using a Bunsen burner.
    • Always light the Bunsen burner with the air hole covered by the collar.
    • Always light a match and hold it above the Bunsen burner barrel before turning on the gas tap.
    • Never turn on a gas tap on without a Bunsen burner attached and a match lit above the barrel.
    • Extinguish the match immediately after lighting the Bunsen burner.
    • Always leave the Bunsen burner on the yellow safety flame when you are not heating anything.
    • Always leave the Bunsen burner on the blue heating flame when you are heating something.
    • Only put something in a flame if you are instructed to by your teacher.
    • Never put your hand in a Bunsen burner flame.
    • Never reach across a Bunsen burner flame.
    • Always extinguish a Bunsen burner flame by turning off the gas tap.
    • Never attempt to blow out a Bunsen burner flame.
    • If the flame accidentally goes out, turn the gas tap off immediately.
    • If there is a fire, immediately turn off the gas tap and alert your teacher.

 
Bunsen burner safety glasses

(Image: Airman 1st Class Micaiah Anthony, US Air Force)

 

Summary

  • The main parts of a Bunsen burner are:
    • The barrel.
    • The base.
    • The air hole.
    • The collar.
    • The gas inlet and rubber hose.
  • There are two types of Bunsen burner flame
    1. The yellow safety flame.
    2. • Less hot flame.
      • Highly visible
      • Use whenever you are not heating something.

    3. The blue heating flame
    4. • Hotter flame.
      • Harder to see.
      • Use only when you are heating something.

  • There is a correct procedure that must be followed every time you light a Bunsen burner:
    • Always wear the correct safety gear.
    • Always light a Bunsen burner with the collar closed.
    • Only turn the gas tap on when a lit match is above the barrel.
    • Always extinguish a Bunsen burner flame by turning off the gas tap.
  • Always follow the safety rules when using a Bunsen burner.
    Only use a Bunsen burner for the purposes instructed to you by your teacher.

 
Bunsen burner flames

(Image: Jan Fijałkowski, Wikimedia Commons)

 

(Header Image: biker3, Adobe Stock)

 

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