Earth and Space Sciences
Earth and Space Sciences
This domain tests Earth's materials and processes, weather and the water cycle, and the solar system. Questions ask you to explain patterns such as day and night, seasons and Moon phases, and to connect human activity with resources and natural hazards.
Earth's structure and materials
- Earth has a crust, mantle and core. The crust is thin compared with the mantle.
- Rocks are igneous (cooled magma), sedimentary (layered deposits) or metamorphic (changed by heat and pressure). Soil forms from weathered rock plus humus and has layers.
- Weathering breaks rock, erosion moves the fragments, and deposition drops them elsewhere.
- Fossil fuels and minerals are non-renewable; soil, water, wind and sunlight are renewable if managed carefully.
Water cycle and weather
- The water cycle: evaporation, condensation, precipitation and collection. It has no starting point.
- Clouds form when moist air cools. Weather is day to day; climate is long term. Instruments include the rain gauge, thermometer, anemometer and wind vane.
- Floods and droughts are hazard events that affect soil, crops and homes.
Solar system and sky
- The Sun is a star. Eight planets orbit it in order: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
- Earth rotates on its axis once in about 24 hours, giving day and night. It revolves around the Sun once a year.
- The Moon orbits Earth and does not emit light; its phases depend on how much of the Sun-lit half we see.
- Seasons are caused by Earth's tilted axis, not by distance from the Sun. A solar eclipse occurs when the Moon blocks the Sun; a lunar eclipse occurs when Earth's shadow falls on the Moon.
Resources and hazards
Reduce, reuse and recycle; conserve water and soil. Earthquakes and volcanoes occur mainly at plate boundaries. Protecting vegetation and maintaining drainage can reduce flood risk.
Worked example
Why is it night in Guyana when it is day in India?
Reasoning: Earth is a sphere and rotates. The Sun lights one half at a time. Guyana and India are on opposite sides, so when one faces the Sun the other is in shadow. The cause is Earth's rotation, not the Sun moving around Earth.
Traps that cost marks
- Explaining seasons by distance from the Sun instead of axial tilt.
- Saying the Moon makes its own light.
- Swapping rotation and revolution.
- Saying the water cycle begins with rain.
- Treating soil as lifeless dirt rather than a mixture of rock particles, humus, air and water.