C
On your marks… get set… breathe
Lesson 2 (continued)
What is the relationship between peak flow and height?
Student notes for this experiment are on pages 28–29.
Aim
Peak flow is a measure of the maximum velocity of air that a person can generate
through a forced exhalation. In this experiment students will measure their height and
their own peak flow and determine if there is a relationship between the two. Students
can then go on to explore a hypothesis of their own choice to find out if there are any
relationships between peak flow and types of sport, e.g. swimming.
Equipment
From the kit box
From your school
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2 peak flow meters
optional:
disposable mouthpieces
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stadiometer
tape measures
Safety
Students should have a break between each peak flow test.
● Identify any students with asthma: they may not wish to participate or may wish to
use their inhaler before they take part in the peak-flow measurement.
● Identify any student with heart/lung problems; they should be allowed to decline to
take part in the peak-flow measurement.
● Ensure disposable mouthpieces are not shared, although they may be re-used by
individual students.
● Students attempting to outdo each other in peak flow rates may become faint or
suffer headaches; discourage such competition.
● Ensure students carry out the activities in a suitable place, clear of any
obstruction.
Running the experiment
1 Students will use a stadiometer or tape measure to measure their standing and
sitting heights. A stadiometer is a medical device for measuring height. The sliding
horizontal headpiece will allow students to measure height more accurately. To do
this they will need access to a wall. When students measure their height, they
should do this without shoes and with a ruler or other flat object to level the top of
their head. They should take a deep breath in, breathe out, relax and stand tall
without going on tiptoes. You could ask three students to measure a fourth
student’s height without taking the precautions above to illustrate the variation in
readings they will obtain. Refer to the diagram on the Student sheet. Students will
not need to repeat this if they have already done it for Experiment C.
2 Students will then measure their peak flow using the peak flow meter (please refer
to the 'How to use the equipment in the box' section on page 7 of this guide).
Each student must use their own disposable mouthpiece when using the
Ages
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26
11–14
C
peak flow meter. Students must throw their mouthpiece away at the end of the
experiment.
3 When students are taking their peak flow readings the following important
instructions must be followed:
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The pointer on the peak flow meter should be set to the end of the meter
(below the 60 mark) before students blow into it.
Students must stand up.
Students should hold the peak flow meter so that their fingers are clear of the
scale and slot.
They should hold the meter horizontally when blowing into it.
4 See the Student sheet on pages 28–29 for the protocol for obtaining evidence.
5 Students take three readings and take the highest value.
6 Students can then write their results on the whiteboard or a record sheet.
Expected results
Peak flow in this age group will be mainly dependent upon height. The peak flow of
taller students is likely to be greater than those of other students. Peak flow is also
likely to be higher in those who take part in regular exercise. Students with asthma
are likely to have a lower peak flow and may be used to measuring their peak flow. In
adults peak flow varies with height, age and sex.
Live Data Zone
Your students can enter their peak flow and heights from this experiment, together
with data from Experiment D, into the ‘Live Data Zone’ section of the In the Zone
website (www.getinthezone.org.uk). See Teacher notes on page 35 for 11–14
Lesson 3.
Ages
11–14
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