We've changed our name — alarm-clock.org is now timeandspace.science. Same tools, same pages, new address.
Three towns, three stories
Grades 3–4 · 35 minutes · Describe the pattern. The driving question: Why is it summer here and winter in Sydney — on the same day? Every step below is a link that opens the exact view — one link puts the projector and every student screen on the same sky. Part of the lesson plans by topic and grade.
Before the lesson — what this assumes
- Assumes: reading a time and a duration (hours and minutes).
- Assumes: day and night come from the Earth turning — one Play of a single day in the simulator shows the town riding into the dark half.
- Pre-work: find your town on its sunrise page and write down today's day length.
The plan — every step carries its minutes
The minutes are there for the teacher's pacing — and so that any single step can be handed to a student as their own five-minute lesson. See students teach the class.
What they should find — the teacher's key
- Singapore ≈ 12 h all three dates; mid-latitudes swing hours; Anchorage from ~5.5 h to ~19.5 h.
- The equator-to-pole gradient is the finding; the tilt as its cause is deliberately left as the next band's mechanism.
Standards: Builds toward 5-ESS1-2 (seasonal daylight data).
What the picture fakes: Every sunrise is computed in the browser from the date and the place, never looked up, so any date works. The solver assumes a flat horizon — a mountain to the east makes the real sunrise later than the page says, and the methodology pages state the accuracy bounds.
Questions to chase on your own
For the student who wants more — each answerable with the tools, no teacher required:
- Find a city where today is LONGER than in your town. (Hint: try the other hemisphere — Sydney.) Why might that be?
- Which day of the whole year is your town's longest? Hunt for it with the date picker.
Questions the curious actually ask
Real questions, mostly from real kids — the kind that sound simple and open trapdoors. Worth raising in class before someone raises them for you:
Why isn't the hottest day the longest day?
The longest day is around June 21 — check yours — but the hottest weeks come in July and August. Why the lag? Because the land and the oceans are still filling up with heat, like an oven that keeps warming after you turn the dial. As long as each day brings in more heat than the night lets out, temperatures keep climbing — even as the days start shrinking. The sea does the same thing harder: beach water is warmest in September, months after the sun's peak.
Do people at the equator have seasons?
Not ours. Day length barely moves — check Singapore on any date, it's near 12 hours year-round — and there's no warm-and-cold cycle to hang "summer" on. Instead the year is carved into wet and dry seasons as the planet's rain belt migrates north and south, chasing the overhead sun. And there's a bonus strangeness: at the equator the sun passes straight overhead twice a year, and on those days at noon, you have almost no shadow.
If we're closer to the sun in January, shouldn't January be warmer?
It is — in Australia: look at Sydney's daylight today against your own town's. That's the tell that unravels the whole "closer = summer" idea: Earth really is 3 million miles closer to the sun in early January, and the southern hemisphere really is in summer then. The distance change is real but small (about 3%); the tilt's effect on sun-angle and day length is enormous. The 7–8 lesson turns this exact trap into a full period of hypothesis-testing.
Go further — beyond this site
- NASA Space Place: What Causes the Seasons? — confirms the pattern the table just showed.
Same question, other grades
Each grade band re-asks this topic's question one level deeper — observe it, describe the pattern, measure it, explain the mechanism, quantify it and question the model. This page is the describe the pattern rung.
Teachers: make this lesson better
You are the one standing in front of the class, so you will see what we cannot: a task that runs long, a question that lands better another way, a grade level pitched wrong, a topic we should build next. Tell us — improvements go into the page, and if we use yours, your class gets the credit on it, the same promise the classroom request form makes.