Why Taiwan has earthquakes
Explain why earthquakes follow plate boundaries, using this month's real earthquakes.
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Events
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Learn how the Earth works
Earthquakes, volcanoes, climate zones, satellites and the aurora, explained with this week's real data. 25 short lessons, 15 of them play right here in your browser.
Units and lessons
Each lesson asks you to predict, then shows the data, then names a common mistake and ends with three check questions.
Restless Earth
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Magnitude: one step is a big step
Understand that magnitude is logarithmic, and tell magnitude apart from the shaking felt at a place.
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Ridges, trenches and faults
Name the three main kinds of plate boundary and what each one builds.
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Volcanoes and the Ring of Fire
Explain why most volcanoes sit on plate boundaries and how hot spots make the exceptions.
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Why some earthquakes make a tsunami
Explain how a tsunami starts, how it travels and what to do near the coast.
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How deep do earthquakes go?
Read earthquake depths and use them to trace a plate sinking into the mantle.
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Earthquake early warning
Explain P- and S-waves and how an early-warning system wins a few seconds.
Air in motion
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The global wind machine
Explain the pattern of the trade winds, the doldrums and the westerlies from uneven heating and the Earth's spin.
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The monsoon year
Explain why the wind over Taiwan and India reverses between winter and summer.
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How a typhoon forms
Name the conditions a typhoon needs and explain where its energy comes from.
Reading the weather
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Why mountains are colder
Use two cities' typical years to show how temperature falls with height.
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The daily swing
Use the forecast timeline to see why some places swing more than others between day and night.
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Highs, lows and the spin
Read isobars, find highs and lows, and link them to wind direction, wind speed and weather.
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How strong is that wind?
Read wind speed and the Beaufort scale, and explain why wind is strongest over open sea.
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How radar sees rain
Explain how weather radar measures rain, how it differs from a forecast, and why mountains make wet and dry sides.
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Reading a typhoon forecast
Read a typhoon track and forecast cone, and explain why slow, rainy typhoons are dangerous.
Ocean
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The warm sea and its currents
Read a sea temperature map, find the warm pool, upwelling and warm currents, and explain why the sea changes temperature slowly.
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El Niño and La Niña
Describe what changes in the Pacific during El Niño and La Niña, and read NOAA's index.
Climate
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Climate zones
Read a Köppen climate map and link the zones to latitude, wind belts and the distribution of land.
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The sea effect
Use two cities' typical years to show how the sea narrows the gap between summer and winter.
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Seasons: tilt, not distance
Explain the seasons with the tilt of the Earth's axis, using day length and the height of the noon Sun.
Space around Earth
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Why the ISS track moves west
Explain what keeps a satellite in orbit and why its ground track shifts with each orbit.
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How your phone knows where it is
Explain how satellite navigation turns signal travel times into a position.
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Your compass and the wandering pole
Explain why a compass does not point to true north and where the Earth's magnetic field comes from.
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Why the sky lights up: aurora
Explain where aurorae appear and why, and read a live aurora forecast and the Kp index.