Lab:
How to Use a Bunsen Burner
Purpose:
To learn how to use and adjust the Bunsen Burner, and to determine
the hottest part of the flame.
Materials:
Bunsen Burner
Procedure:
Part One:
Index Card
Match
“pin”
Adjusting the Bunsen Burner
1. Examine your Bunsen Burner. The gas outlet at your lab station is connected to a
rubber tube. The rubber tube is then connected to the gas inlet of your Bunsen
Burner.
2. Located the barrel of your Bunsen Burner. The barrel is the long vertical tube.
Locate the air vents of your Bunsen
Burner (if so equipped). The air vents
are on the outside of the barrel. The air
vents allow you to control the amount of
air that is mixed with the gas of the
Bunsen Burner (in the barrel). If you
have too much air or too little air in the
barrel, then the flame will not burn
properly. To begin with, the air vents
should be located at about the “half-way
point”.
3. When you turn on the gas you will hear a hissing sound. Either use the flint
lighter or the electrical lighter supplied by Mr. Zim. Hint: If you try to light the
Bunsen Burn from directly on top of the barrel, the force of the gas may blow out
your match. Try lighting the burner from the “sides”.
4. When the burner is lit, adjust the air-gas mixture so that your flame is blue and
silent and does not flicker. The perfect flame is about 10 cm high, pale blue, and
almost colorless. If the flame is very large and/or orange-yellow, then there is not
enough air mixing with the gas. You have to open the air vents and possibly
reduce the flow of gas. Some Bunsen Burners have a needle valve on the bottom
to control the amount of gas flow. For other Bunsen Burners, the gas flow is
control by turning the outlet on your desk. If the flame separates from the burner,
then there is too much air in the barrel; therefore partially close the air vent.
5. The flame is extinguished by closing the gas outlet on your lab table. Allow each
of your lab partners to practice the lighting and extinguishing procedure.
Procedure: Part Two:
Finding the hottest part of the flame.
1. Turn on your Bunsen Burner, adjusting it to produce a pale blue flame. You
should see a flame that resembles two cones, an inner cone which may darker
blue, and an outer cone which is lighter in color. SKETCH your observation
in the data section below.
2. Is the flame equally hot throughout the
flame? Let’s find out. With the help of
your teacher insert an index card in the
flame as diagrammed below. REMOVE
the card immediately when it starts to
scorch. Closely examine the scorched
pattern on the card. SKETCH the
scorched pattern in the data section below.
3. Now we will perform another test. Make
sure your Bunsen Burner is off. Stick a
pin through a match 0.5 cm below the
match head. The object is to suspend the
match inside the barrel of the Bunsen
Burner using the pin to keep the match
from falling in the barrel. Turn on the
gas, light the burner the usual way and
record your observations in your data
section below. Turn off your Bunsen
Burner.
Data and Observations: (Record on a Separate Piece of Paper)
1.
2.
3.
4.
5.
6.
7.
8.
9.
Carefully SKETCH the blue flame and label the color regions.
Carefully SKETCH the scorched pattern of the index card.
Compare the two Sketches. Is there any connection between the sketches?
Judging from the two sketches, where do you deduce is the hottest part of
the flame. Describe
What happened to the match
What could you conclude about the temperature of the flame where the
match was located?
If you wish to heat an object strongly, where in the flame should you place
it?
What are the four parts of the Bunsen Burner?
If the flame is orange yellow, what does that mean?