Science s2 exam

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Biosphere

All living organisms and the places where life exists.

Atmosphere

The layer of gases surrounding Earth.

Hydrosphere

All water on Earth, including oceans, rivers, lakes, groundwater, ice and water vapour.

Lithosphere

Earth’s rigid, rocky outer layer.

Carbon cycle

The movement of carbon between Earth’s spheres.

Photosynthesis

The process plants and some other organisms use to make sugars from carbon dioxide and water using light energy; it removes carbon dioxide from the air.

Respiration

A cellular process that releases usable energy from glucose and releases carbon dioxide.

Decomposition

The breakdown of dead organisms and waste by decomposers, returning carbon and other materials to the environment.

Combustion

Burning a fuel; it releases energy and commonly releases carbon dioxide.

Carbon sink

A store that absorbs and holds more carbon than it releases over a given period.

Fossil fuels

Coal, oil and natural gas formed from ancient organic matter over long periods.

Earth's Spheres Examples

Examples include: trees/animals (biosphere), air/oxygen (atmosphere), oceans/rivers (hydrosphere), and rocks/soil (lithosphere).

Carbon Storage Locations

Where carbon is stored: in living things, the atmosphere, oceans, rocks, and fossil fuels.

Effect of Bushfires & Fossil Fuels on Atmosphere

Burning fossil fuels and bushfires release large amounts of stored carbon into the air as carbon dioxide, increasing atmospheric carbon dioxide levels.

Greenhouse gas

A gas in the atmosphere that absorbs and re-emits infrared radiation.

Natural greenhouse effect

The natural process that keeps Earth warm enough to support life.

Enhanced greenhouse effect

Additional warming caused by increased greenhouse gases, especially from human activities.

Climate change

Long-term changes in average temperatures and weather patterns.

Mitigation

Action that reduces greenhouse gas emissions or increases the removal/storage of greenhouse gases.

Reforestation

Replanting or restoring forests, which can store carbon as trees grow.

Renewable energy

Energy from sources replenished naturally, such as sunlight and wind.

Carbon capture

Capturing carbon dioxide from an emission source or the air so it can be stored or used.

Cultural burning

A planned, careful burning practice guided by Aboriginal and Torres Strait Islander knowledge and practices; it can reduce fuel loads and help care for Country.

Greenhouse Gases Examples

Examples include carbon dioxide, methane, and water vapour.

Greenhouse Gas Mechanism

Greenhouse gases absorb outgoing infrared radiation from Earth's surface and re-emit it in all directions, keeping the lower atmosphere warmer.

Natural vs Enhanced Warming

The natural greenhouse effect maintains a stable temperature for life, while the enhanced greenhouse effect causes extra warming due to increased human-made greenhouse gas emissions.

Tectonic plate

A large, moving section of Earth’s rigid outer layer.

Mantle convection

The slow movement of hot mantle material rising and cooler material sinking; it helps drive plate movement.

Plate tectonics

The theory that Earth’s outer shell is divided into moving plates.

Continental drift

The idea that continents have moved over geological time.

Divergent boundary

A boundary where plates move apart; new crust can form, for example at a mid-ocean ridge.

Convergent boundary

A boundary where plates move towards each other; it may produce trenches, volcanoes or mountains.

Transform boundary

A boundary where plates slide past each other; earthquakes can occur.

Mid-ocean ridge

An underwater mountain chain where new oceanic crust forms as plates move apart.

Ring of Fire

A zone around the Pacific Ocean with many volcanoes and earthquakes.

Evidence for Continental Drift

The puzzle-like fit of South America and Africa and matching fossils found on different continents.

Electric current (I)

The rate at which electric charge flows; measured in amperes (A).

Electron

A negatively charged subatomic particle that moves through metal wires in a circuit.

Conductor

A material that allows electric charge to flow easily, such as copper.

Insulator

A material that resists the flow of electric charge, such as rubber or plastic.

Voltage (V)

The energy transferred per unit of charge; measured in volts (V).

Resistance (R)

How much a component opposes current; measured in ohms (Ω).

Series circuit

A circuit with one path for current; adding more globes generally increases total resistance and reduces current.

Parallel circuit

A circuit with separate branches; each branch has the same voltage as the supply in an ideal circuit.

Ammeter

An instrument used to measure current; it is connected in series.

Voltmeter

An instrument used to measure voltage across a component; it is connected in parallel.

Ohm’s Law Formula

V = I × R (Voltage equals current multiplied by resistance). To find resistance: R = V ÷ I.

Series vs Parallel Bulb Failure

In a series circuit, if one globe fails, the whole circuit breaks (all go out). In a parallel circuit, if one globe fails, the other branches stay lit because they have independent paths.

Ammeter vs Voltmeter Placement

An ammeter is placed in series to measure current, while a voltmeter is placed in parallel across a component to measure voltage.

Crest

The highest point of a transverse wave.

Trough

The lowest point of a transverse wave.

Amplitude

The maximum displacement from the resting position; for sound, larger amplitude is heard as greater loudness.

Wavelength

The distance between matching points on consecutive waves, such as crest to crest.

Frequency

The number of complete waves passing a point each second; measured in hertz (Hz). Higher sound frequency means higher pitch.

Electromagnetic wave

A wave that can travel through a vacuum; examples include radio waves and visible light.

Refraction

The change in direction of a wave when its speed changes as it enters a different material.

Normal

An imaginary line drawn at 90° to a surface where a light ray hits.

Angle of incidence

The angle between the incoming ray and the normal.

Angle of reflection

The angle between the reflected ray and the normal; it equals the angle of incidence.

Sound Pitch and Loudness

Greater amplitude creates a louder sound, while greater frequency creates a higher-pitched sound.

Thermal energy

Energy associated with the movement and interactions of particles in a substance.

Conduction

Transfer of thermal energy through a material without the material moving as a whole; it is especially effective in metals.

Particle model

A model that describes matter as being made of tiny particles that are always moving.

Independent variable

The factor deliberately changed in an investigation.

Dependent variable

The factor measured or observed in response to the change.

Control variable

A factor kept the same so the test is fair.

Trend

The general pattern shown by data.

Fair test

An investigation in which only the independent variable is deliberately changed while other relevant factors are controlled.

Conduction in Metals Explanation

Heat causes particles to vibrate faster; these vibrating particles bump into neighboring particles, passing thermal energy through the material (especially fast in metals due to free electrons).