Year 7 Practical Skills for Inquiry Learning (continued)
Exploring the 'open' flame For the teacher:
For the students: Results:
Students can now go back to their work stations in their pairs and
carry out activities 3, 4 and 5. The last one can be difficult to get
to work and you may need to do it as a demonstration after they
have had a go. The key is to balance the bottom end of the glass
tube on the edge of the chimney – this helps to hold it steady while
yellow colour comes from in this instance – especially if they ask
a student lights the flame at the other end. It is difficult to hold it
next lesson.
steady otherwise since it must be held with the metal tongs.
3.
3. As the gauze is held horizontally in the flame in each of the 3
positions, the part in contact with the flame will get hot enough
to glow red. The diagrams below show where the red glow will
appear in each position. Where part of the gauze is in the ‘blue
As the gauze is held horizontally in the flame in each of the 3 positions, the part in contact with the flame
inner cone’ (position 1) it remains the ‘unheated’ gauze colour.
will get hot enough to glow red. The diagrams below show where the red glow will appear in each
A ring
of part
red
appears
this cone’
as (position
the flame
outside
the blue gauze
position.
Where
of the
gauze is in around
the ‘blue inner
1) it remains
the ‘unheated’
colour. A ring of red appears around this as the flame outside the blue cone heats the gauze.
cone heats the gauze.
rcelain is held
the ‘open
flame’.
• above
Students
are now
going to explore the ‘open flame’ more
• Work in pairs again at your practical work station and share
the experimental work between you.
red hot
• Follow the given instructions and be sure to look carefully at
the diagrams that show you what to do.
3. Using tongs, hold a piece of wire gauze horizontally across
ons in their pairs
and carry out activities 3, 4 and 5. The last
the ‘open’ flame at different places (see diagram). Draw
may need to do it diagrams
as a demonstration
after they
have of had
a go.
in your science
journals
what
you observe when
glass tube on the you
edge
of
the
chimney
–
this
helps
to
hold
it
look down on the gauze in each position.
other end. It is difficult to hold it steady otherwise since it must
pen flame’ more closely in their same pairs.
rk station and share the experimental work between you.
e to look carefully at the diagrams that show you what to do.
and lodge it across the barrel of the Bunsen burner. Light
the burner with the air hole open and record what you see
happening.
match
match just below the
the Bunsen burner .
en and record what
red hot
gauze colour
4. When
the
Bunsen is lit
with the air hole open – the match does not ignite for some time. In the case of the ‘closed’ flame it will
ignite
at once. the Bunsen is lit with the air hole open – the match does
4. When
5. A small flame which is a replica of the main Bunsen flame will light at the end of the tube away from the
not ignite for some time. In the case of the ‘closed’ flame it will
flame.
ignite at once.
All of these small activities explore the ‘open’ flame and in particular provide evidence for the inner blue
cone of the ‘open’ flame being composed of unburned gas. The students have made observations in each of
5. A small flame which is a replica of the main Bunsen flame will
the 3 activities which actually give them the evidence which can lead them to this conclusion – so you are
light
the end
the tube away from the flame.
developing
their at thinking
skills of
again.
After all the experiments have been completed you can draw the class together and get them to share their
All of these small activities explore the ‘open’ flame and in
results. If there are any discrepancies in these, get the students to suggest the best way to sort them out.
particular
provide
for they the
inner
blue
cone
of any
the problems
‘open’
Hopefully,
since you
are moving evidence
round the lab as
work
you can
spot and
sort out
as and
if they
arise! being
Students need
to understand of
that unburned
they are just learning
practical
techniques have
and it is not
flame
composed
gas. their
The
students
a problem if they need some help at times – this is how they will improve.
ze horizontally across
ee diagram). Draw
what you observe when
position. 4. Stick a sewing pin through an unlit match just below the head
.
red hot
closely in their same pairs.
made observations in each of the 3 activities which actually give
When all the results are sorted they can get into small groups and talk about what they think their
them the evidence which can lead them to this conclusion – so
observations can tell them about this ‘open’ flame. Back together as a class they can share ideas and
you the are
their
thinking
skills
again.
‘argue
toss’ developing
and hopefully come
up with
the idea that
the inner
blue cone is unburned gas. This then is
an example of observations giving them direct evidence on which to base their conclusions.
After all the experiments have been completed you can draw the
They may come up with other ideas about the flame – and you may want to get them thinking about the
class
together
and the get
them
their completely
results. burned.
If there are any
colour
and the
fact that, with
air hole
open, to
the share
gas is getting
in these,
get the
suggest
the adds
best
way
In discrepancies
addition there are opportunities
to discuss
when students
and how to use to each
flame, which
to their
practical
skills
and
the
small
experiments
add
to
their
manipulative
skills.
to sort them out. Hopefully, since you are moving round the lab as
they work you can spot and sort out any problems as and if they
arise! Students need to understand that they are just learning
their practical techniques and it is not a problem if they need some
We now have some extra safety precautions to add to the SAFETY poster up on the wall (which needs
help at times – this is how they will improve.
continual updating). The students have also learned some new practical skills (again – need to keep an
updated list?) and we constantly need to check that they are using these correctly. If students deliberately or
When all the results are sorted they can get into small groups
and talk about what they think their observations can tell them
about this ‘open’ flame. Back together as a class they can share
ideas and ‘argue the toss’ and hopefully come up with the idea
that the inner blue cone is unburned gas. This then is an example
of observations giving them direct evidence on which to base
their conclusions.
pin
Bunsen
chimney
5. Hold a piece of glass tubing in metal tongs and rest one end
They may come up with other ideas about the flame – and you
may want to get them thinking about the colour and the fact that,
with the air hole open, the gas is getting completely burned.
tongs and rest one
on the chimney of the Bunsen within the blue inner cone. Hold
the blue inner cone.
a lighted match to the other end. Record what you see.
glass tube
66
SCIENCE EDUCATIONAL NEWS VOL 68 NO 1