Science Practical’s will start from Tuesday (15th September 2020)
The practical skills involved are:
– manipulation, measurement and observation,
the collection of simple data to an appropriate accuracy, choosing the right
range and distribution of values
– presentation of data and observations in a
– analysis, conclusions and evaluation, using
and justifying the correct number of significant figures
– plotting of a graph and calculation of a
gradient. In the second paper this involves the use of logarithms and plotting
error bars on graphs
– estimating the uncertainties in measurements
made and identifying the most significant sources of uncertainty
– calculating the uncertainty in the value of
a calculated quantity made from two or more measurements each with their own
– evaluation of the method involved and
– planning an experiment, including
identifying dependent and independent variables and quantities that remain
constant, identifying any risks involved
Developing practical skills prepares
students for studies beyond A Level in physics, engineering or in
physics-dependent vocational courses. Practical’s also help students
develop abilities and skills that are useful in everyday life and encourage
safe practice. These practical skills help to develop attitudes such
as a concern for accuracy and precision, initiative, inventiveness and a spirit
These skills are important in employment and
go far beyond mere knowledge of facts. A good practical course also
helps to develop an interest in the subject of physics itself and complements
the study of the theory, showing that scientific theory is ultimately grounded
by experiment. The amount of practical apparatus required does not
have to be enormous because working within the resources available is another
useful ability. It’s important to remember that students can learn a lot
from practical work that goes wrong as well as from experiments that
work perfectly every time.
Many students at A Level may not have had much
experience of practical work and may not consider themselves to be
very ‘practical’, but there is no need to be afraid of simple experiments.
Students need practice in setting up simple apparatus and to be happy in
carrying out the experiment by themselves. When a student has enough experience
of simple apparatus then they face the challenge of writing a method where they
must choose the apparatus and method for themselves. This might be for an
experiment that differs from any that they have previously seen and shows their
inventiveness and initiative.
Students may also
believe practical work to be a mathematical exercise where there is a
right and a wrong answer. This is not the case. Every reading has an inherent
uncertainty and students need to be happy to estimate uncertainties in simple
quantities, such as the measurement of length and time by either repeating
readings or taking the smallest scale reading on the instrument used. They also
need to realize that the uncertainty is only an estimate and is itself not
There are a few mathematical challenges,
particularly for those not studying mathematics at A Level. These include the
use of logarithms and combining uncertainties, where a real familiarity with
percentages is a useful skill. However, the average student can learn the
necessary skills with a reasonable amount of application.
1) Think actively about every topic. Do you
understand what is going on? If not, then ask a question.
2) Know how to estimate uncertainty as the
smallest scale division or, better, half the range in the readings.
3) After every experiment write down:
– the steps that you actually took during the
– whether each quantity was dependent, independent or kept constant
– major difficulties
4) Realize that readings in a table are
measured, usually, to the same precision, i.e. to the same number of decimal
places, but that calculated quantities should be given to the smallest number
of significant figures in the quantities used in the calculation.
5) Take care when plotting graphs.
– does your graph cover half the page
horizontally and vertically?
– does it have units on both axes?
– check your points are accurate
– use a long ruler when drawing a straight line
– show your working in finding the gradient
1) Remember that practical work is
important; it is a component of your examinations. Therefore, make the most of
whatever practical experience that you are given and don’t think of
it as relaxation time away from theory work.
2) Remember that practical work is
related to the rest of the syllabus. If you are not sure why you are doing
the practical – ask your teacher to explain. When you are told that
you will be doing a practical investigation, write down what you
think are the aims of the practical work and what you hope to get
3) If you have a practical partner,
then agree responsibilities. For example, if you are measuring the rate of a
reaction by following the change in the volume of gas produced, one of you can
measure the time and help countdown to the next reading, while your partner can
read the volume.
4) If you are going to do an
assessed practical, then ask your teacher what criteria she or he is going
to use when allocating the marks.
5) Try and maintain a
good balance between your awareness of safety and a confident use of the
apparatus. You should by now know how to use a Bunsen burner safely and the
difference between gentle heating and strong heating, even some advanced level
students think that gentle heating involves a yellow Bunsen burner flame.
The has a chapter on basic techniques. If
this textbook is available, then take a look at this chapter.
Before they can embark on AS & A
Level practical work with confidence, students should be familiar
with the use of a typical school laboratory. This includes things such as
balances, measuring cylinders, beakers, pipettes (or syringes), heating
apparatus and thermometers. It is also important that students know how to work
safely when carrying out practical work.
A knowledge of basic biochemical tests such as
the tests for starch, glucose, protein and lipids is useful as these are often
revisited at AS & A Level. There is also an assumption that students
are aware of simple tests from Cambridge IGCSE™ chemistry, such as using
universal indicator paper and testing for using limewater to test for carbon
dioxide gas. These chemical tests are often used when carrying
out practicals at AS and A Level biology.
Students should also understand how to plan
valid experiments with standardized variables and repeats. They should also
know how to draw results tables that display data effectively. Evaluating the
design of simple experiments, such as recognizing the level of accuracy of equipment
is also a useful skill to reinforce before AS & A Level. All these skills
help to provide a good foundation upon which to build.
For biology experiments, results can often be
unpredictable! Living organisms often do not respond in the ways that we
expect. For example, a piece of pond weed in an investigation into the effect
of light intensity, may not photosynthesis due to several reasons. Students
need to be patient, accept that all results are valid and explore the reasons
for results not being as expected. Many students think that getting unexpected
results is essentially the mark of a bad experiment – in reality, getting the
‘wrong results’ can be a learning experience in itself. Students should also
not be scared to ‘have a go’ and be encouraged to try again if something did
not seem to work first time.
1) Be confident and keep trying even if a
technique is difficult
2) Don’t expect results to always go the way you planned – remember that living
organisms can be very different to one another
3) Work safely – always wear eye protection and risk assess everything
4) Be organized – keep all your equipment tidy on your bench
5) Enjoy practical work – it is your opportunity to apply your
knowledge to the real thing
Science Practical’s will start from Tuesday (15th September 2020) at
GreenHall Academy Gulberg Campus.
GreenHall Academy Gulberg Campus:
GreenHall Academy Johar Town Campus:
GreenHall Academy DHA Phase 1 Campus:
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