eduKate Learning Manual • Interactions • Forces and Motion • Primary Science

WAIT, WHAT? A Pull Does Not Need a Rope

Pull open a drawer and your hand is in direct contact with it. But gravity pulls objects toward Earth without a rope, hook or visible connection. Magnets can attract or repel without touching first.

That tells us something deeper than “a force is a push or pull”. A force is an interaction that can change motion or shape. Some interactions require contact. Others act across a distance.

Why This Is Worth Learning

Pushes and pulls are the entry point into mechanics. If the foundation is too vague, later ideas—gravity, friction, magnetism, balanced forces and motion—become lists to memorise instead of one connected system.

The useful questions are:

• Which object is experiencing the force?
• What is interacting with it?
• In which direction does the force act?
• Does it change motion, shape, or neither because other forces balance it?

The Core Primary Model

The Singapore Primary Science syllabus introduces a force as a push or a pull.

A force can:

• move a stationary object;
• speed up or slow down a moving object;
• stop a moving object;
• change the direction of motion;
• change the shape of an object.

These are effects of forces. They are not the definition of force itself.

Contact Forces

Some forces arise when objects touch.

• Your hand pushes a door.
• A string pulls a toy.
• A table pushes upward on a resting book.
• Friction acts where surfaces contact.
• A compressed spring pushes outward.

In each case, identify the pair of interacting objects. “There is a push” is incomplete unless you can say what pushes what.

Non-Contact Forces

Other forces can act without direct contact.

• Gravitational force: Earth pulls objects toward it.
• Magnetic force: magnets can attract or repel appropriate magnetic objects or other magnets.

The detailed mechanisms belong to their own lessons. Here, the important conceptual upgrade is that “push” and “pull” describe force effects and directions, not necessarily visible contact by a hand.

A Force Acts on an Object

Force explanations become much clearer when the learner names the object being studied.

Instead of saying:

“There is gravity.”

say:

“Earth exerts a downward gravitational force on the ball.”

Instead of:

“There is friction.”

say:

“The floor exerts a frictional force on the sliding box.”

That small language change forces the interaction to become explicit.

You Can Push Without Making Something Move

Push against a sturdy wall. You are clearly exerting a force, yet the wall may not move noticeably.

This immediately destroys another weak rule:

force present ≠ motion must occur.

Other forces and structural support can balance the effect. The force can also produce tiny deformations too small to notice easily.

Forces Come from Interactions, Not from Motion

A rolling ball does not carry a “motion force” inside it. Motion describes what the object is doing. Force describes an interaction acting on the object.

This distinction prepares the learner for Newton’s first law: an object can continue moving without a forward net force if no unbalanced force changes its motion.

How Do We Know a Push or Pull Is Stronger?

We can measure force using a spring balance or force meter. NASA force-measurement systems use the same general principle at much higher precision: a known physical element deforms under load, and the deformation is calibrated against force.

At Primary level, a spring balance lets us move from:

“That felt stronger”

to:

“The measured force was larger.”

Worked Reasoning

Situation: A child pulls a wagon forward using a handle. Friction acts on the wagon, and gravity pulls it downward.

Weak answer: “The wagon moves because it is being pulled.”

Stronger answer: “The child exerts a forward pull on the wagon through the handle. Other forces also act, including friction and gravity. Whether and how the wagon’s motion changes depends on the combined effect of these forces.”

The stronger answer names the object, interaction, direction and competing forces.

A Deeper Enrichment: Interactions Work Both Ways

When your hand pushes a wall, the wall also pushes your hand. You can feel that force as pressure on your skin.

At higher levels, Newton’s third law formalises this paired nature of interactions. The two forces act on different objects. This page does not own the full third-law treatment, but the enrichment helps prevent the idea that forces are one-way commands.

How Do We Investigate Pushes and Pulls?

A good investigation turns a vague action into measurable variables.

• Choose the object being acted on.
• Measure or control the applied force.
• Specify the direction.
• Keep the surface and object unchanged.
• Measure the resulting motion or deformation.
• Repeat the test.

This is how a simple “push the toy” activity becomes Scientific Inquiry.

Safe Investigation: Push, Pull, Measure

Use a lightweight object, a spring balance and a clear level surface.

• Measure the pull needed to start the object moving.
• Measure a smaller pull that does not move it.
• Change the direction of the pull.
• Observe what changes in the motion.
• Repeat and record.

Do not pull heavy furniture, use fragile objects or create trip hazards.

Common Misconceptions — and Repairs

• “All pushes and pulls require touching.” Gravity and magnetic force can act without direct contact.
• “If something does not move, no force is acting.” Forces can be balanced or insufficient to overcome other effects.
• “Moving objects contain force.” Force is an interaction; motion is a state of the object.
• “A pull is always toward a person’s body.” Force direction is defined relative to the objects and interaction, not the observer.
• “One force explains everything that happens.” Several forces can act simultaneously.

Model Limit: “Push or Pull” Is the Doorway, Not the Whole House

Calling a force a push or pull is extremely useful in Primary Science. At later levels, forces are described by magnitude, direction, interaction type and mathematical vector models.

The Primary definition remains valuable because it points to the observable idea of interaction. It should not be mistaken for the full physics of fields and forces.

Transfer Challenge

For each situation below, identify the object being studied, the interacting object or field, whether contact is required, and the force direction:

• a magnet attracting a steel paper clip;
• a hand pushing a trolley;
• Earth pulling a dropped ball;
• a string pulling a kite;
• a table supporting a book.

Then explain why “the object moved” is not enough evidence to identify every force acting on it.

Mastery Check

You have mastered pushes and pulls when you can identify the object experiencing the force, name the interaction, distinguish contact and non-contact examples, separate force from motion, and recognise that several forces can act at the same time.

Teaching Guide — Use This Last

For parents, tutors and teachers: keep asking “Who pushes whom?” or “What pulls what?” until the learner stops speaking about force as a free-floating thing.

Start with obvious contact examples, then introduce gravity and magnetism to break the “must touch” assumption. Next push a wall to break the “force must cause visible motion” assumption. Finally, give a moving object and ask whether it contains a force. The desired endpoint is an interaction model.

RFE Check: What Should Survive After the Page Is Closed?

The learner should leave with a compact diagnostic: Which object? What is interacting with it? Is the force a push or pull, in what direction, and what effect—if any—does the combined force produce?

Singapore Curriculum and Trusted References

• MOE: 2023 Primary Science Teaching & Learning Syllabus
• NASA Glenn: Newton’s Laws and Forces
• NASA Glenn: Spring Gage
• NASA: Force Measurement Systems

Explore the Science Learning Library. The reverse frontier continues only after another live registry collision check.