1. The Blue Marble – What does Earth look like from a distance?
2. Eratosthenes’ measurement – Can we measure the size of the Earth with a stick?
2.a Making Eratosthenes’ measurement
2.b Eratosthenes’ measurement results
2.c Eratosthenes and the flat Earth model
3. Meteor arrival rates – When is the best time to see meteors? And why?
4. Airy’s coal pit experiment – How does gravity change down t’ pit?
5. Horizon dip angle – Is the horizon actually horizontal?
6. Gegenschein – Can we observe an effect of the sun being behind the Earth?
7. Supernova 1987A – How was this event detected all over the Earth?
8. Earth’s magnetic field – Why is it the shape it is?
9. The South Pole – Where is the South Pole on a flat Earth?
10. The Sagnac effect – Can we measure the Earth’s rotation speed at different places?
11. Auroral ovals – Where do aurorae occur, and why?
12. The sun – How far away and how big is it, and does it shine in all directions?
13. Hydrostatic equilibrium – How tall a mountain can there possibly be?
14. Map projections – Why can’t we draw an accurate map of the whole Earth?
15. Trilateration – How can you draw a scale diagram of distances between places on Earth?
16. Lunar eclipses – What shape is the Earth’s shadow?
17. Light time corrections – Do we see astronomical events when they happen?
18. Polar motion – Why do Earth’s North and South Poles move over time?
19. Bridge towers – Are large suspension bridge towers parallel?
20. Rocket launch sites – Where is the best place to build a launch facility?
20.a Rocket launch sites update
21. Zodiacal light – Can Queen guitarist Brian May help us prove the Earth is a globe?
22. Plate tectonics – How does the Earth’s crust move over time?
23. Straight line travel – What happens if you travel in a straight line across the Earth?
24. Gravitational acceleration variation – How and why does Earth’s gravity vary across the world?
25. Planetary formation – Why does the Earth even exist at all?
26. Skyglow – How does light pollution vary with distance from cities?
27. Camera image stabilisation – How does the Earth’s shape affect camera technology?
28. Stereo imaging – What does Earth look like from two places at once?
29. Neutrino beams – Can neutrinos be sent from one particle physics lab to another?
30. Pulsar timing – How do you detect previously undiscovered pulsars?
31. Earth’s atmosphere – Why doesn’t our atmosphere leak away into space?
32. Satellite laser ranging – How do we measure the distance to satellites? Or the moon?
33. Angle sum of a triangle – Can we measure Earth’s curvature using a big triangle?
34. Earth’s internal heat – How hot is it inside the Earth, and why?
35. The Eötvös effect – Do you weigh more or less on a moving ship, and why?
36. The visible stars – What stars can you see at night from different places on Earth?
37. Sundials – How do sundials work? And in what ways don’t they work?
38. Lunar temperature modulation – Why does the Earth’s temperature vary with the phase of the moon?
39. Seismic wave propagation – How quickly are earthquakes detected in different locations?
40. Falling objects – Do falling objects really fall straight down?
Colour naming experiment – Do people name colours consistently?
Colour naming experiment, part 2 – Analysing the results.
Pendulum experiment – Measuring the strength of Earth’s gravity.