YEARS 7–12 IDEAS FOR THE CLASSROOM
Year 7 Practical Skills for Inquiry Learning – Part 3 (continued)
different audiences (literacy) and only one of these is the
scientific reporting genre. In this instance they have produced
a poster or flow-chart which records their efforts.
What the students do:
• Work in groups and assign roles.
• Each group has one Alka Seltzer tablet, a film canister, a 10
ml measuring cylinder and a Pasteur pipette. Put 2 ml of water
into the canister, add ¼ of an Alka Seltzer tablet, then very
quickly put on the lid and put the canister onto the bench.
• If experiments must indeed be written up, it is good to let the
students write/report their experiments in their own words
from the beginning of Year 7 – no copying from board, OHP
or text book – and check their efforts formatively. Not only
will they develop many more essential skills, and you can
provide individual assistance, but you will also get to know the
strengths and weaknesses of each student early in the year.
• Wait to see what happens and make observations – (give them
time to play!)
What the teacher does:
6. Pop goes the weasel!
• If students have not used a measuring cylinder before they
will need to be taught the skills of using one accurately
(additionally, they should add it to their apparatus list): stand
it on a flat surface to read the volume; fill the last few drops to
get to the mark using a teat pipette; eyes level with the scale to
read; etc. ... These are new skills which can be added to their
‘New Skills’ list and it is expected that they will use these in the
future, whenever they need to measure out volumes of liquids.
This is another fun activity which can be used in various ways to
give students further practice with their developing investigation
skills. The students may well want to play around with it for a
while, and it is good to let them – just have a large supply of
Alka Seltzer! Once they have had some fun – and wiped up the
inevitable mess – you can set them some tasks that will require
investigation. Since this is essentially the same reaction as the
‘sherbet fizz’, you may decide not to ask “What causes the fizz?”
again unless you decide your class needs to revisit this or if time
has passed since the previous activity was carried out.
• Explain the activity to students (see point 2 above) then
circulate, watch and listen! They should at least all observe
the fizzing and foaming in the liquid when the lid flies off. I
have found that most people, including pre-service teachers
and grandchildren, want to play and try to make a bigger
‘explosion’ so it is worth letting them have some time to play
around – varying the volume of water and the quantity of Alka
Seltzer).
Requirements:
• film canisters + lids (if you can get them!)
• Alka Seltzer tablets + box(es)
• When they have settled down they can then be set some
further tasks. Perhaps start with “Find out as much as you can
about what is going on in the canister that makes the lid fly off”
– and see what they come up with. If this is too vague for some
groups, ask them to investigate the answers to more specific
questions:
• Pasteur (teat) pipette + bulb
• 10 ml measuring cylinder
• + whatever the students might ask for, e.g. test tubes,
racks
– Which of the ingredients of Alka Seltzer (X, Y, and Z)
caused the fizz? (sodium bicarbonate (Z) and citric acid
(Y) + H 2 O). They have tackled similar questions in the
Baggie Science and Sherbet Fizz experiments, and must
have used ‘scientific method’ ideas to find out the answer.
Again it is important to encourage them to explain to you
how they arrived at the answer to the question (assuming
it was correct groups that find that their answer is incorrect
or incomplete when comparing with other groups may be
directed to have another go). This will ultimately lead to the
steps in the scientific method.
• crushed up aspirin in a small container labelled X
• citric acid in a small container labelled Y
• sodium bicarbonate in a small container labelled Z
• paper cake cases are useful for distributing chemicals if
you don’t have ‘small containers’
• paper towels
• hidden from view
• lime water
– Why does the fizz make the lid pop off? (because a gas is
formed and it needs to escape – because it takes up more
space?) They will need to be able to explain how they know
that ‘fizz’ equals a gas being formed – this has already
been discussed in Baggie Science (Part 1).
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SCIENCE EDUCATIONAL NEWS VOL 68 NO 3