Teaching Forces
Background knowledge for
teachers
NEWTON’S 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.
Newton’s laws can confuse learners. The following slide
provides simple explanations of Newton’s Laws of Motion.
At primary it is good for children to experience and discuss
the effects of forces.
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.
I’d rather push a Mini than a 4X4!
3. To every Action Force there is an equal and
opposite Reaction Force.
If you shove me I’ll shove you back
(at the same time)!
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
Common pupil myth
An object which does not move has no
forces acting on it.
Balanced forces
• Are there any forces acting on this cup?
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.
Types of forces
• Pushing Forces
• Pulling 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.
Buoyancy
• A few ideas for getting them talking, thinking and
helping them to construct new meanings.
Lava Lamp
Dancing Raisins
Water Density
Gravity
Learners commonly have misconceptions
about gravity e.g. The Earth has gravity
because it has an atmosphere.
Therefore, the Moon can’t have
because it doesn’t have an atmosphere.
Gravity
Challenging learners’ ideas
about gravity
• Ask learner’s 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 Galileo’s theory
• Watch videos of astronauts on the moon and
discuss how and why gravity is weaker on the
moon
Fun with gravity
• Galileo
• Astro-Blaster
• Centre of Gravity
Friction – possible activities
• O-Wings
• Gripping Rice!
• Potato Spears
Air resistance – possible activities
• Streamlining
• Rockets
Great resources
The Surfing Scientist
www.abc.net.au/science/surfingscientist/
Planet Science Experiments
http://www.planet-science.com/categories/experiments.aspx
Little Book of Experiments
(downloadable version requires STEM Learning account to access)
https://www.stem.org.uk/elibrary/resource/27187/the-little-book-ofexperiments