Teaching Forces

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Teaching Forces

• Background knowledge for teachers

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NEWTONS LAWS OF MOTION

• 1. An object will stay at rest, or move at a
  constant speed, unless acted upon by an
  unbalanced force.

2. The acceleration of an object acted upon by an
unbalanced force is directly proportional to the
magnitude of the force and inversely proportional
to its mass.
3. To every action force there is an equal and
opposite reaction force.
Newtons laws can confuse learners. The
following slide provides simple explanations of
Newtons Laws of Motion. At primary it is good
for children to experience and discuss the
effects of forces.
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All Complicated Forces Explained

• 1. Balanced forces cause objects to stay at rest
  or travel at a constant speed.

A bullet travelling through space just keeps on
going.
2. Unbalanced Forces cause objects to speed up or
slow down.
Id rather push a Mini than a 4X4!
3. To every Action Force there is an equal and
opposite Reaction Force.
If you shove me Ill shove you back (at the same
time)!
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Elicit their ideas

• Get learners to discuss what they think prior to
  investigating
• Use interesting, engaging activities to get them
  thinking/wondering
• Find out any misconceptions
• All of the above are important before learners
  can new construct new meaning

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Common Pupil Myth

• An object which does not move has no forces
  acting on it.

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Balanced Forces

• Are there any forces acting on this cup?

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Hang About!

• Try strings and arrows!
• Which forces are acting on
• This object?
• With a difficult concept such as upthrust
• from a table it can be useful to get learners
• to think about examples they can visualise
• e.g. a nail pushing up on a string, water
  pushing up on a boat.

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Types of Forces
Different types of forces should be explored with
learners. They need hands on opportunities to
experience and investigate these and think about
and discuss their ideas about everyday examples.

• Pushing Forces

• Pulling Forces

• Friction

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Buoyancy

• A few ideas for getting them talking, thinking
  and helping them to construct new meanings.

Lava Lamp
Dancing Raisins
Water Density
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Gravity
Learners commonly have misconceptions about
gravity e.g. The Earth has gravity because it
has an atmosphere.

• Therefore, the Moon cant have Gravity
  because it doesnt have an atmosphere.

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Challenging learners ideas about gravity

• Ask learners to draw forces diagrams which show
  where gravity is pulling when people are at
  different locations on Earth
• Use tennis balls that look the same but one is
  injected with water to explore Galileos theory
• Watch videos of astronauts on the moon and
  discuss how and why gravity is weaker on the moon

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Fun with Gravity

• Galileo
• Astro-Blaster
• Centre of Gravity

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Friction possible activities

• O-Wings

• Gripping Rice!

• Potato Spears

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Air Resistance Possible Activities

• Streamlining
• Rockets

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Great Resources

• www.abc.net.au/science/surfingscientist/
• www.planet-science.com/
• Little Book of Experiments
• www.planet-science.com/experiment/