Why seasons happen
Explain how axial tilt changes daylight and solar angle, then predict which hemisphere experiences summer at a chosen point in the year.
Start a discussionWhat would happen to seasons if axial tilt were 0°?
Teachers
Bring Earth science into the room.
Start with a real landscape, explore the process in 3D, and give students something to explain. These free lesson notes help teachers and geography clubs prepare a discussion, lead a demonstration or print a handout. You can use every resource without an account.
01
Observe
Notice a feature and ask a question.
02
Tinker
Change one variable in the model.
03
Explain
Connect the result to a process.
04
Check
Explain the evidence in your own words.
62 of 62 lessons
Planet
Earth rotation and the terminator
Explain how Earth’s eastward rotation produces day and night, and relate a 15° difference in longitude to one hour of solar time.
Start a discussionWhich way does Earth rotate, viewed from above the North Pole?
Moon phases and Sun–Earth–Moon geometry
Use the positions of the Sun, Earth and Moon to explain the changing illuminated shape we see during a lunar month.
Start a discussionAt first quarter, where is the Moon relative to the Sun and Earth?
Solar system
Compare the sizes and orbital periods of planets, and explain why planets farther from the Sun take longer to orbit.
Start a discussionWhy does a planet speed up near perihelion?
Sun and Earth
Explain how latitude and the Sun’s declination affect the solar energy received at noon and across a whole day.
Start a discussionThe 1361 W/m² reference applies to…
Universe scale
Compare distances within and beyond the Solar System, using light-travel time to make their scale easier to understand.
Start a discussionA light-year measures…
Geologic time
Read dates in millions of years and compare the unequal durations of major intervals in Earth’s history.
Start a discussionMa means…
Eclipses
Explain how the Sun, Earth and Moon must align for an eclipse, and identify the regions of total and partial shadow.
Start a discussionThe umbra is…
Tides
Explain how the relative positions of the Moon and Sun produce the difference between spring and neap tides.
Start a discussionWhy two bulges?
Solar altitude and sun path
Compare the Sun’s daily path at different latitudes and explain how the season changes noon altitude and day length.
Start a discussionNoon solar altitude is lowest in London around…
Interior & Plates
Earth’s interior
Identify Earth’s main layers and explain how seismic waves provide evidence for a liquid outer core.
Start a discussionWhich layer is liquid metal?
Plate boundaries
Compare the motion at three types of plate boundary and explain how each produces characteristic landforms.
Start a discussionThe Mid-Atlantic Ridge is which boundary type?
Continental drift
Compare reconstructed continental positions through time and use fossil and coastline evidence to discuss the former arrangement of Pangaea.
Start a discussionPangaea was…
Hotspots
Use the direction of increasing volcanic age to infer relative plate motion in the Hawaiian and Yellowstone examples.
Start a discussionOlder volcanoes in the main Hawaiian chain generally lie…
Seafloor spreading
Explain how new oceanic crust forms at a ridge and how magnetic stripes record spreading on either side.
Start a discussionNewest crust is…
Folds and faults
Compare the rock deformation caused by compression, tension and sideways motion, using folds and faults as evidence.
Start a discussionIn this upright example, an anticline is…
Isostasy
Explain how the crust responds to loading and unloading, using an ice sheet to explore subsidence and rebound.
Start a discussionIsostasy means…
Wilson cycle
Follow the opening and closing of an ocean basin and relate continental collision to the formation of mountain belts.
Start a discussionThe Wilson cycle is…
Atmosphere
Atmosphere as a thin film
Identify the main atmospheric layers and explain how changes in temperature with height help distinguish them.
Start a discussionWhere does almost all weather happen?
Earth’s energy budget
Trace energy entering and leaving Earth, and explain how reflection and atmospheric absorption affect the surface temperature.
Start a discussionWhat hits the ground first from the Sun?
Thermal circulation
Explain how unequal heating creates a circulation, then apply that reasoning to a coastal breeze and an urban heat island.
Start a discussionA sea breeze at the surface blows…
Wind, PGF and Coriolis
Explain how pressure differences start air moving and how Earth’s rotation and surface friction change its direction.
Start a discussionPGF points…
Three-cell circulation
Locate the Hadley, Ferrel and polar cells and relate their circulation to broad patterns of winds and rainfall.
Start a discussionThe Hadley cell has rising air near…
Fronts as wedges
Compare warm, cold and occluded fronts, and explain how the movement of contrasting air masses produces cloud and rain.
Start a discussionA cold front is…
Cyclone and anticyclone
Compare pressure and airflow around a cyclone and an anticyclone, then relate each pattern to the weather it can bring.
Start a discussionIn the northern hemisphere a midlatitude cyclone spins…
Climate types
Explore the five major climate families and explain how long-term temperature and rainfall patterns shape their global distribution.
Start a discussionKöppen–Geiger classification primarily uses…
Rain shadow
Explain why rising air cools and produces rain on a windward slope, leaving drier conditions on the leeward side.
Start a discussionAir rising on the windward slope…
Water & Carbon
Water cycle stores and flows
Trace water between stores and explain how changes in rainfall or human use affect the amount held in a reservoir.
Start a discussionThe largest store of fresh water is…
Drainage basin
Trace water through a drainage basin and explain how the watershed connects the tributaries to a shared outlet.
Start a discussionA watershed is…
Storm hydrograph
Read the main features of a storm hydrograph and explain how urban surfaces can change the timing and size of peak discharge.
Start a discussionLag time is…
River regime
Compare annual patterns of river discharge and explain how rainfall, snowmelt and dams can change their timing.
Start a discussionA nival regime is driven by…
Ocean currents
Follow the major surface currents and explain how winds and ocean heat transport contribute to regional climate.
Start a discussionA gyre is…
Thermohaline conveyor
Explain how cooling and changes in salinity affect seawater density, then relate sinking and rising water to ocean overturning.
Start a discussionThermohaline means…
Carbon cycle
Trace carbon between fast and slow stores, and explain how burning fossil fuels transfers carbon into the atmosphere.
Start a discussionFossil fuels are…
ENSO and the Walker cell
Compare normal Pacific conditions with El Niño and La Niña, and explain how changes in winds and ocean temperature affect rainfall.
Start a discussionThe Walker cell is…
Groundwater
Locate water in connected pores and explain how pumping changes the water table and flow towards a well.
Start a discussionThe water table is…
Landforms
River long profile
Follow a river from source to mouth and explain how its gradient, channel shape and flow change downstream.
Start a discussionWhere is vertical erosion most important?
Landform types
Compare the elevation and shape of mountains, hills, plateaus, plains and basins using a shared scale.
Start a discussionA plateau is…
River erosion
Explain how river erosion forms waterfalls, gorges and potholes, and distinguish the retreat of a waterfall from the direction of flow.
Start a discussionNick-point retreat leaves…
River deposition
Explain where rivers deposit sediment and compare the formation of point bars, natural levees and deltas.
Start a discussionA slip-off slope is…
River capture
Explain how headward erosion can divert a river’s headwaters and identify evidence left in the old channel.
Start a discussionAn elbow of capture is…
Coasts
Explain how coastal erosion forms caves, arches and stacks, and how longshore drift and groynes change the movement of beach sediment.
Start a discussionLongshore drift moves sediment…
Glacial landforms
Explain how moving ice shapes a valley, and distinguish the direction of ice flow from the advance or retreat of its margin.
Start a discussionAn arête is…
Karst
Explain how water dissolves limestone along joints to form surface grooves, sinkholes and underground passages.
Start a discussionGrykes are…
Wind landforms
Explain how wind erodes rock and transports sand, then identify the wind direction from the shape of a barchan dune.
Start a discussionA barchan’s horns point…
Mass movement
Identify the main parts of a rotational slump and explain how rainfall can reduce the stability of a slope.
Start a discussionA rotational slump moves on…
Periglacial landforms
Explain how repeated freezing and thawing produce ice wedges and patterned ground in cold landscapes.
Start a discussionPeriglacial means…
Soils & Rocks
Rock cycle
Trace several possible routes through the rock cycle and explain how melting, cooling, pressure and weathering transform rock.
Start a discussionMetamorphism normally means…
Soil profile
Identify the horizons in a soil profile and compare how water, organic matter and parent material influence their development.
Start a discussionThe R horizon is…
Soil texture triangle
Use the proportions of sand, silt and clay to classify a soil, then explain how its texture affects water movement.
Start a discussionClay particles are…
Weathering
Compare how freezing water, weakly acidic water and growing roots break down rock in place.
Start a discussionFrost shattering is…
Soil erosion
Compare soil loss under different vegetation cover and explain how runoff carries sediment away from a slope.
Start a discussionExported sediment is…
Soil catena
Compare soil profiles from the crest to the foot of a slope and explain how water and sediment movement connect them.
Start a discussionA catena is…
Hazards
Earthquakes
Locate the focus and epicentre of an earthquake and compare how different seismic waves travel through Earth.
Start a discussionThe focus (hypocentre) is…
Volcanoes
Explain how magma viscosity influences volcanic form and eruption style, using shield and composite volcanoes as examples.
Start a discussionShield volcanoes form from…
Tsunami
Explain how seafloor displacement generates a tsunami and why its speed and height change as it enters shallow water.
Start a discussionA tsunami starts with…
Tropical cyclone
Identify the eye, eyewall and rainbands of a tropical cyclone and explain how warm ocean water supports its circulation.
Start a discussionThe eyewall is…
Storm surge
Explain how strong winds and low atmospheric pressure can raise coastal water levels, especially over a shallow shelf.
Start a discussionA storm surge is…
Skills
Contours ↔ 3D terrain
Relate contour spacing and shape to the height and slope of a landscape, then distinguish a valley from a spur.
Start a discussionContour lines that form a V pointing uphill usually mark a…
Graticule and coordinates
Use latitude and longitude to locate a point on Earth, and relate longitude to differences in local solar time.
Start a discussionLatitude measures…
Map projections
Compare how map projections represent a curved Earth on a flat surface, identifying the distortions each introduces.
Start a discussionOn a Mercator world map Greenland looks…
Grid references
Read and plot a six-figure grid reference by locating the easting before the northing.
Start a discussionYou read a grid reference…