SCIENCE

What is a force

A force is a push or pull acting on an object that can change its motion or shape

What are contact forces

Contact forces act only when two objects are physically touching

What are examples of contact forces

Friction, air resistance, water resistance and upthrust are contact forces

What is friction

Friction is a force resisting motion between two touching surfaces

How can friction be increased

Friction can be increased using rough surfaces or materials such as rubber

How can friction be reduced

Friction can be reduced using lubricants or smooth surfaces

What is lubrication

Lubrication is the use of oil or grease to reduce friction

What is air resistance

Air resistance is a frictional force acting against objects moving through air

What is water resistance

Water resistance is a frictional force acting against objects moving through water

What is upthrust

Upthrust is the upward force exerted by fluids on floating objects

What are non-contact forces

Non-contact forces act without physical contact between objects

What are examples of non-contact forces

Gravity, magnetism and static electricity are non-contact forces

What is gravity

Gravity is the force attracting objects towards Earth

What is magnetism

Magnetism is a force exerted by magnets on magnetic materials such as iron

What is static electricity

Static electricity is caused by the build-up of electric charge on surfaces

What is weight

Weight is the force exerted on an object by gravity

What is mass

Mass is the amount of matter in an object measured in kilograms

What is the unit of force

Force is measured in newtons symbolised by N

How are forces represented

Forces are represented using arrows showing size and direction

What happens when forces are balanced

Balanced forces are equal in size and opposite in direction causing no change in motion

What happens when forces are unbalanced

Unbalanced forces cause an object to speed up, slow down or change direction

What is extension

Extension is the increase in length of a stretched object

What is Hooke’s Law

Hooke’s Law states extension is proportional to force applied

What does proportional mean

Proportional means both quantities increase at the same rate

What is the limit of proportionality

The point where extension no longer increases proportionally with force

What is the elastic limit

The point beyond which a spring cannot return to original shape

What is a force meter

A force meter measures force using a calibrated spring

What is pressure

Pressure is the force acting on a certain area

What affects pressure

Pressure depends on the size of the force and the area it acts on

What is the equation for pressure

Pressure = force ÷ area

What is the unit of pressure

Pressure is measured in pascals symbolised by Pa

Why do sharp knives cut better

Sharp knives have a smaller surface area producing greater pressure

Why do snowshoes prevent sinking

Snowshoes spread weight over a larger area reducing pressure

What is sound

Sound is a form of energy produced by vibrations

What is vibration

A vibration is a rapid back-and-forth movement

What is pitch

Pitch describes how high or low a sound is

What determines pitch

Pitch depends on the frequency of vibrations

What is frequency

Frequency is the number of vibrations or waves per second

What is the unit of frequency

Frequency is measured in hertz symbolised by Hz

What is amplitude

Amplitude is the maximum displacement of a wave from its rest position

What determines loudness

Loudness depends on the amplitude of vibrations

How are sounds produced in humans

Vocal cords vibrate as air passes over them

How does sound travel

Sound travels through solids, liquids and gases by vibrating particles

Why can sound not travel through a vacuum

A vacuum contains no particles to transfer vibrations

What is a sound wave

A sound wave is a longitudinal wave transferring energy through vibrations

What is a longitudinal wave

A wave where particles vibrate parallel to direction of travel

What is a transverse wave

A wave where particles vibrate perpendicular to direction of travel

What is superposition

Superposition occurs when waves overlap and combine

Why does sound travel faster in solids

Particles are closer together allowing vibrations to transfer faster

What is an echo

An echo is a reflected sound wave

What is echolocation

Echolocation uses reflected sound waves to detect objects

How do bats use echolocation

Bats emit high-frequency sounds and detect returning echoes

What is sonar

Sonar uses ultrasound reflections to detect underwater objects and depth

What is ultrasound

Ultrasound is sound with frequency above 20000 Hz

What is infrasound

Infrasound is sound with frequency below 20 Hz

What is the human auditory range

Humans normally hear frequencies between 20 Hz and 20000 Hz

How does the ear detect sound

Sound waves vibrate the eardrum and impulses are sent to the brain

What is the cochlea

The cochlea is a spiral structure containing hair cells detecting vibrations

What is the auditory nerve

The auditory nerve carries electrical impulses from ear to brain

What are decibels

Decibels are the units used to measure sound loudness

Why is ear protection important

Loud sounds can damage hearing permanently

What is a microphone

A microphone converts sound vibrations into electrical signals

What is current electricity

Current electricity is the flow of electric charge through a conductor

What is current

Current is the rate of flow of electric charge

What is the unit of current

Current is measured in amperes symbolised by A

What is a component

A component is a device used in an electrical circuit

What is a switch

A switch opens or closes a circuit

What happens when a switch is closed

Closing a switch completes the circuit allowing current to flow

What is a conductor

A conductor allows electric charge to flow easily

What is an insulator

An insulator resists the flow of electric charge

What is an ammeter

An ammeter measures electric current

How is an ammeter connected

An ammeter is connected in series in a circuit

What is a series circuit

A series circuit has all components connected in one loop

What happens to current in a series circuit

Current is the same at all points in a series circuit

What happens when bulbs are added to a series circuit

Adding bulbs decreases current and bulbs become dimmer

What is a parallel circuit

A parallel circuit contains branches with separate paths for current

What are advantages of parallel circuits

Components work independently and others stay on if one breaks

What happens to current in a parallel circuit

Current splits between branches and adds together again

What is voltage

Voltage is the energy transferred per unit charge

What is the unit of voltage

Voltage is measured in volts symbolised by V

What is a voltmeter

A voltmeter measures voltage across a component

How is a voltmeter connected

A voltmeter is connected in parallel across a component

What is resistance

Resistance is the opposition to current flow

What is a resistor

A resistor reduces current by increasing resistance

What is a variable resistor

A variable resistor changes resistance in a circuit

What is a fuse

A fuse melts and breaks the circuit if current becomes too high

What is a circuit breaker

A circuit breaker automatically cuts off excessive current

What are hazards of electricity

Electricity can cause burns, fires and fatal electric shocks

How can electrical risks be reduced

Avoid damaged wires, water near plugs and overloaded sockets

What is energy

Energy is the ability to do work or cause change

What is the unit of energy

Energy is measured in joules symbolised by J

What is a kilojoule

A kilojoule is equal to 1000 joules

What is a balanced diet

A balanced diet contains all nutrients needed for health

What are nutrients

Nutrients are substances needed for energy, growth and repair

What is energy transfer

Energy transfer is the movement of energy from one store to another

What is chemical energy

Chemical energy is stored in fuels, food and batteries

What is kinetic energy

Kinetic energy is the energy of moving objects

What is thermal energy

Thermal energy is energy stored in hot objects

What is strain energy

Strain energy is stored in stretched or compressed objects

What is gravitational potential energy

Gravitational potential energy is stored due to height above ground