Year 9 Physics - Full Master Revision Sheet

Flashcards for Year 9 Physics revision, covering key definitions, forces, energy, electromagnetism, waves, particle model of matter, history of the atom, and pressure.

Accuracy

How close a value is to the true value.

Precision

How close repeat readings are to each other.

Repeatability

Same person, same method yields similar results.

Reproducibility

Different person or method yields similar results.

Control Variable

Kept constant to make it a fair test.

Independent Variable

The thing you change in an experiment.

Dependent Variable

What you measure in an experiment.

Gravity

Pulls objects toward Earth.

Friction

Resists motion.

Air Resistance

Drag in air.

Tension

Pull in rope/chain.

Normal Force

Support force from surface.

Upthrust

Fluid pushes upward.

Resultant Force

A single force that has the same effect as all acting forces combined.

Mass

Matter in object (kg).

Weight

Gravitational force (N).

Hooke’s Law

Force is proportional to extension until elastic limit.

Elastic Limit

Point where spring stops returning to original length.

Lever

A simple machine that turns about a pivot.

Moment

Force × Distance from pivot.

Friction

Resists motion. Can be useful or unwanted.

Drag

Friction in fluids (air/water).

Elastic Deformation

Returns to shape.

Plastic Deformation

Permanent change in shape.

Kinetic Energy

Moving car.

Thermal Energy

Boiling water.

Gravitational Potential Energy

Book on shelf.

Elastic Potential Energy

Stretched band.

Chemical Energy

Food, fuel.

Light Energy

Torch.

Sound Energy

Music.

Mechanically Energy Transfer

Forces cause motion.

Electrically Energy Transfer

Electric currents.

By Heating Energy Transfer

From hot → cold.

By Radiation Energy Transfer

Waves (light, sound).

Energy Dissipation

Energy spreads out to surroundings, mostly as heat or sound.

Efficiency

Percentage of energy usefully transferred.

Electromagnet

Made by wrapping wire around iron core + adding current.

Transverse Waves

Oscillations perpendicular to direction of travel (light, water).

Longitudinal Waves

Oscillations parallel to direction (sound).

Amplitude

Height from rest to crest.

Wavelength

Distance between two crests/troughs.

Frequency

Waves per second (Hz).

Speed

Wave speed = Frequency × Wavelength

Reflection

Wave bounces off surface.

Refraction

Wave bends as it enters different medium (speed changes).

Constructive Interference

Bigger wave (adds up).

Destructive Interference

Cancels out (subtracts).

Solid

Fixed positions, vibrate only.

Liquid

Close, slide past each other.

Gas

Far apart, move freely.

Density

Mass ÷ Volume.

Specific Latent Heat

Energy needed to change state without temperature change.

Fusion

melting/freezing.

Vaporisation

boiling/condensing.

Specific Heat Capacity

Energy to raise 1kg by 1°C.

Internal Energy

Total energy in particles (kinetic + potential).

Gas Pressure

Caused by collisions with container walls.

Democritus Model

Atoms are indivisible.

Dalton Model

Solid spheres.

Thomson Model

Plum pudding (electrons in positive “soup”).

Rutherford Model

Nuclear model (dense nucleus).

Bohr Model

Electrons in shells.

Chadwick Model

Neutron added.

Pressure

Force ÷ Area.

Atmospheric Pressure

Caused by weight of air particles.

Work Done

Measure of energy transfer when a force moves an object through a distance.