Physical science conceptions

Core concepts

When exploring the natural world, the wide expanse of knowledge leads us to develop the big ideas or core concepts of science. Teachers and students can use these concepts to explain and make predictions about a range of related phenomena in the natural world. Through the curriculum, these concepts are introduced and developed according to the age and stage of the students.

	Forces affect the motion and behaviour of objects	Energy can be transferred and transformed from one for to another and is conserved within systems
F	Describe how objects move and how factors including their size, shape or material influence their movement	Concept not covered at this year level
Y1	Describe pushes and pulls in terms of strength and direction and predict the effect of these forces on objects’ motion and shape	Concept not covered at this year level
Y2	Concept not covered at this year level	Explore different actions to make sounds and how to make a variety of sounds, and recognise that sound energy causes objects to vibrate
Y3	Concept not covered at this year level	Identify sources of heat energy and examine how temperature changes when heat energy is transferred from one object to another
Y4	Identify how forces can be exerted by one object on another and investigate the effect of frictional, gravitational and magnetic forces on the motion of objects	Concept not covered at this year level
Y5	Concept not covered at this year level	Identify sources of light, recognise that light travels in a straight path and describe how shadows are formed and light can be reflected and refracted
Y6	Concept not covered at this year level	Investigate the transfer and transformation of energy in electrical circuits, including the role of circuit components, insulators and conductors

Energy

Alternative conceptions

Energy can be transferred and transformed from one for to another and is conserved within systems.

This list of alternative concepts is not meant to be comprehensive, but instead aims to provide a starting point.

Alternative conception	Accepted conception
Energy is used up.	Energy may be transformed or transferred but it is always conserved.
Energy is a ‘thing’	Materials and objects can have energy transferred to them.
Energy and force are interchangeable	A force is an external effect that can cause an object to change its speed, shape, or direction. Leaning on a desk applies a push force on the desk. This force exists even if the desk does not move (it could cause change if the net force was unbalanced). Force is applied to an object, not transferred. Energy is a property of a system associated with the extent of movement of an object or the amount of heat within it. Energy changes from one form to another can be tracked.
Only living things have energy.	Energy can be transferred between objects. Batteries have chemical energy, cars have kinetic/motion energy.
Only objects in motion have energy.	Potential energy is the energy stored in a coiled spring, in a battery (chemical energy), or in an object that can fall.
Loudness and pitch are the same thing.	Pitch is how high or low a note is, while loudness is how loud or soft the note is.
Sound moves faster in the air than solids.	Sound needs particles to be transmitted. The closer together the particles (solid) the faster the sound will move.
You can see and hear an object far away at the same time.	Light travels faster than sound.
You can scream in space.	Sound requires a medium (with particles close enough to bump together) to be transmitted. This does not occur in space.
Heat is a kind of substance.	Heat is a form of energy that can be transferred or transformed.
Things expand when heated to make room for heat.	When objects are heated, they particles gain kinetic/movement energy. This faster movement means they take up more space and the object can expand.
Heat travels like fluid through objects.	Heat travels by conduction, convection, or radiation.
Objects in the same room can be at different temperatures (metals will be colder than wood).	Metals are good conductors of heat. Touching metal in a cold room will conduct the heat away from your body (making your hand and the metal feel cold). Wood does not conduct heat as well as metal. This keeps the heat in your hand (wood feels warmer than metal).
Things wrapped in an insulator will warm up.	An insulator maintains the heat in an object. A heat source is needed for an object to ‘warm up’.
The eyes produce light (cartoon-like) so we can see objects.	Light is a form of energy that comes from a source (not human eyes).
We see an object when light shines on it.	We see objects when the light bounces off an object and reaches our eyes.
White light is a colour.	The primary colours of light are green, blue, and red. When these are mixed, they produce white light.
A prism adds colour to light.	The different wavelengths of visible light bend in different amounts as they pass through a prism. This spreads the colours/wavelengths and produces a rainbow.
The grass is green because it produces green light.	The green leaves of grass reflect most of the green light (and absorb other colours). This is why we see the green colour.
The primary colours of light are the same as paint.	The primary colours of light are green, blue, and red. Mixing red and green light produces yellow light.
When light moves through a coloured filter, the filter adds the colour to the light.	A coloured filter selectively absorbs some colours and lets others through. For example, a red filter only lets red light through.
Light from a bulb only extends out a certain distance and then stops.	Light is spread over a greater area as it moves away from the source. This means there is less that reaches our eyes.
A mirror reverses everything.	Mirrors reverse images left to right (not up and down)
Light does not reflect from dull surfaces.	We see an object because it is a light source or the light has been reflected from its surface.
Light from a bright light travels further than light from a dim light.	The brightness of a light indicates the number of photons (packets of light) that are able to travel from the source to your eye. The light always travels the same distance but spreads out. More photons will reach your eye even when far away.
Static electricity and current electricity are two different things.	Both static and current involve electrically charged particles. In static electricity, the charged particles do not have a pathway to move. Current electricity has a pathway (usually wire).
Energy in an electric circuit is used by a light globe	Electrical energy is transformed at the globe to light and heat energy.
Batteries store electrical energy.	Batteries store chemicals (chemical energy) that react to produce electricity in connecting wires.
You only need 1 wire to make a circuit.	Electricity must be able to flow from the negative terminal of a battery to the positive terminal. Most electrical cords that plug into the mains power contain at least 2 wires to complete a circuit.
The plastic in the wires keeps the electricity in (like water in a pipe).	Wires do not need plastic coating for the electrical current to flow. It does prevent potential short circuits.
Current is ‘used up’ in a circuit	The current stays the same value in all locations of a series circuit.
The current moves from one end of the battery to the light.	When the battery is connected to a circuit, the current starts flowing in all parts of the circuit at the same time.
Positive current leaves one end of the battery and negative current leaves the other end, these clash at the light bulb.	When the battery is connected to a circuit, the current (electrons from negative to positive terminals) starts flowing around the circuit at the same time.
Voltage is energy.	Voltage is a measure of the electrical potential energy in a circuit.
Touching a high-voltage wire will kill you.	Birds are able to sit on a high voltage wire. If an object was to touch a high voltage wire at the same time they were touching the ground, current would flow through them and cause damage.
The bigger the battery, the more voltage.	The voltage provided by the battery is determined by the manufacturer. Button batteries can be 3 v, while AAA batteries are 1.5 v.
Alternating current (AC) moves all the way around a circuit and back again.	When the battery is connected to a circuit, the current (electrons from negative to positive terminals) starts flowing round the circuit at the same time. Alternative current changes direction 50 times/second.

 

Force

Alternative conceptions

Forces affect the motion and behaviour of objects.

This list of alternative concepts is not meant to be comprehensive, but instead aims to provide a starting point.

Alternative conception	Accepted conception
Energy and force are interchangeable	A force is an external effect which causes an object to change its speed, shape or direction. Leaning on a desk applies a push force on the desk even if the desk does not move because the desk pushes back (it could cause change if the net force was unbalanced). Force is applied to an object, not transferred. Energy is a property of a system associated with the extent of movement of an object or the amount of heat within it. Energy changes from one form to another can be tracked.
Forces cause motion	An unbalanced force will cause a change in motion (acceleration or direction).
Faster objects have more force	An object moving fast has a larger amount of kinetic energy. Energy and force are different entities.
Everything that moves, will eventually stop. Rest in the ‘natural’ state of all objects.	Forces need to be unbalanced for motion to change. Things come to a stop when there is a higher friction force than push/pull force.
A continuous force is needed for continuous motion.
An object is hard to push because it is heavy.	Large objects resist a change in motion (inertia). This will depend on the amount of friction between the object and the surface.
Friction is not a force.	Friction is a force that resists the movement of one surface over another.
Friction is only present when something is moving.	Friction force resists movement in a stationary object if there is a force trying to move it (eg pushing on a large stationary rock).
Friction always needs to be removed from a system.	The friction between car tyres and the road allows the car to move forwards.
Friction gradually uses up the forward push or pull.	An object moving at a constant speed and direction will have a net force of zero (the friction can balance the push/pull force).
Heavier objects fall faster than light objects.	The rate an object falls depends on its size (air resistance). Dropping a medicine ball and a basketball, they will both hit the ground at the same time.
Gravity is due to air pressure or the earth’s spin.	Gravity is proportional to the mass of an object. The larger the mass, the greater the distortion of space and time that is gravity.
Gravity is weaker under water.	The buoyancy of water is a push force that is in the opposite direction of the pull force of gravity. The gravitational force is not weaker.
Objects speed up as they fall because gravity gets stronger closer to earth.	While pull of gravity is marginally smaller on a mountain (a 75 kg person at sea level will weigh 74.75 kg on Mt Everest), objects speed up as they fall due to the acceleration caused by gravity.
There is zero gravity in space	Although it is very small, there is microgravity in space. Astronauts appear weightless because they are in freefall as they orbit the Earth.
An object at rest has no forces acting on it.	An object at rest has no net force acting on it. The gravitational force of a book resting on a table is balanced by the opposite force of the table pushing up on the book.
If an object is moving then it has a net force acting on it.	An object moving at a constant speed and direction will have a net force of zero.
If an aircraft is climbing at a steady rate, then the lift force up will be greater than the downwards force from gravity.	An object moving at a constant speed and direction will have a net force of zero.
Rocket propulsion is due to the exhaust gases pushing on something behind the rocket.	The combustion of fuel releases a gas from the base of the rocket. This push out of gas causes the air at the base to push back and move the rocket upwards.
All magnets are made of iron	Magnets are made of Ferromagnetic metals including nickel, iron and cobalt.
Larger magnets are stronger that small magnets	The magnetic strength does not depend on size
The magnetic and geographic poles are located at the same place.	The magnetic pole is continually shifting.
The magnetic north pole of the Earth is at the north pole.	The magnetic pole is continually shifting. A magnet’s north points to the north pole. This means the geographic north pole is a magnetic south.
All metals are attracted to a magnet.	Aluminium (for example) is not attracted to a magnet.