Realm
Planet
Motion of a tilted sphere
Rotation, revolution, seasons, and the Moon. The clockwork that makes day, night, and the calendar.
Why seasons happen
In December, London is dark by late afternoon while Sydney is in high summer. The Earth is not closer to the Sun in July.
Earth rotation and the terminator
Frost on a window at 07:00 in Leeds is sunlight already on the school roof in Berlin. The Sun did not jump. The planet turned.
Moon phases and Sun–Earth–Moon geometry
A full Moon over Yosemite is the same geometry a student sees from Snowdonia: the Moon is opposite the Sun, not a different Moon.
Solar system
Eight planets, one star. Distances are the lie a classroom model always tells — we exaggerate so you can see them.
Sun and Earth
The solar constant is a number. Latitude is why a playground in London and one in Nairobi disagree.
Universe scale
Powers of ten: Earth, then the system, then the local star field. Keep it short. You cannot see a galaxy in one glance honestly.
Geologic time
A spiral, not a calendar. Units in Ma. Life and continents are marks, not a cartoon parade.
Eclipses
Umbra and penumbra are cones. The Moon’s 5° tilt is why most months miss.
Tides
Two bulges. Spring and neap are alignment, not emotion.
Solar altitude and sun path
A dome over a marked horizon. Date and latitude write the path. Noon altitude and day length fall out.