Air and Flight
This topic lends itself to a number of curriculum ideas. Problem-solving
skills; appreciation of technology and its impact on society; the history
of science/technology; career paths; language development; and flow chart
design could all be covered in a unit on air and flight.
Although the flight activities in this topic can be used for all levels
of primary school, older students tend to get more out of these activities,
as they are able to discuss the concepts at a deeper level. None of these
activities can be explained without an understanding that flight is occurring
through air. The idea of air is thus a prerequisite to understanding flight.
Key concepts of air and flight
The activities in this topic are designed to explore the following key
- Air is all around us.
- Wind is moving air.
- Air fills up spaces if allowed.
- Air can push or cause pressure on things.
- Air slows down falling objects such as paper, balls and parachutes.
- The shape and size of an object affects the nature of airflow around
it, hence the air resistance.
- Planes and other flying things are held up by the force of air on their
- Air in the atmosphere exerts a pressure in all directions.
- The atmosphere can exert a surprisingly strong force on objects.
- 'Sucking' reduces pressure, causing a force imbalance towards the
- The pressure of air is used in many applications (tyres, hoists, etc.).
- Air pressure differences tend to equalise.
- A moving stream of air has reduced pressure.
- Air has weight.
- Air expands on heating, causing a pressure increase if it is contained.
- Hot air is less dense (or more spread out) than cold air, and rises.
- Air consists of a mixture of gases, one of which (O2, dioxide) is
necessary for burning.
- Objects can be shaped to either minimise or maximise the force of
air on them.
- A flat object such as a plane wing, a boomerang or a paper tube can
be supported by forces that arise due to differences in airflow across
the top and bottom surfaces.
- To every action there is an equal and opposite reaction: a stream
of air (or water) forced from a balloon or rocket will cause a force
back on the balloon or rocket to propel it.
- The force from air on a moving object depends on the surface area,
and the shape of the object.
- Wind is moving air.
Students' alternative conceptions of air
Research into students' ideas about this topic has identified the following
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- Younger children often only associate air with wind, which is moving
air. Presumably this stems from a view that only directly observable
entities are real. Thus, they are most likely to interpret 'air is everywhere'
as meaning that air is only outside.
- Young children will think that air moves unaccountably into or out
of enclosed spaces, to explain why there might or might not be air in
upturned glasses, containers or cupboards.
- The wind is caused by trees swaying.
- Fans and moving objects create air (rather than simply set air in
- Students can attribute the causes of these 'air taking up space' or
'air pressure' activities to their own action ('the water comes out because
we lifted our finger', or 'the tissue remains dry because we were careful')
or use explanations based on analogy rather than identify causal mechanism
('the air was trapped'). Thus students can have an 'alternative' view
of the nature of scientific explanation.
- Suction involves creating a vacuum, which causes a negative, pulling
force on objects. In fact 'suction' is often not thought of so specifically
but rather is a term used to describe a class of phenomena. In this sense
the use of the terms 'suction effect', 'suction cap' or even 'suction
force' can be quite helpful in locating causes for movement or identifying
the nature of a phenomenon. It is the identification of the term with
air 'pulling' that is incorrect.
- Pressure only operates in a downward direction.
- Air exerts a force only when it moves.
- Air has no weight or negative weight.
- Hot air has negative weight, which causes it to rise.