Everything for the Space Systems test: study cards, the traps to dodge, a practice quiz at three levels — Foundation, On-Level, and Challenge — and a lab where you label the Sun, Earth and Moon, put the eight phases in order, graph the planets’ distances, and argue the seasons from Chicago’s own numbers. Work here, or print it and use a pencil — both count.
Summer here: the top of the Earth leans toward the Sun, so the light lands almost straight on.
Seasons come from the tilt, not the distance. Everything in this unit works the same way: draw where the Sun, the Earth and the Moon are, and the answer usually appears.
Four things people get wrong
⚠️People often think…
It is summer when the Earth is closer to the Sun.
Earth is actually closest to the Sun in early January, in the middle of our winter. Seasons come from the tilt — and the southern half has summer while we have winter, on the same planet, at the same distance.
If distance caused seasons, both halves would match.
⚠️People often think…
Moon phases are the Earth's shadow falling on the Moon.
Half the Moon is always lit. Phases are about how much of that lit half we can see from here. Earth's shadow on the Moon is a lunar eclipse, and it is rare.
Phases happen monthly. Eclipses barely happen.
⚠️People often think…
A light-year is a very long amount of time.
A light-year is a DISTANCE — how far light travels in a year. Saying a star is 40 light-years away is like saying a town is 40 miles away.
It answers how far, not how long.
⚠️People often think…
Astronauts float because there is no gravity up there.
There is plenty of gravity in orbit — gravity is what an orbit IS. They are falling around the Earth and missing it, and so is everything else in the station, which is why nothing appears to fall.
An orbit is falling and missing.
Draw the three bodies
1Watch one
Why is it summer in Illinois in July?
The Earth's axis is tilted.
In July, our half leans toward the Sun.
The light hits more directly.
More energy on the same patch of ground. Summer.
2Do one with me
Tonight there is a full moon. Draw the three bodies in your head.
Who is in the middle: the Sun, the Earth or the Moon?
How much of the lit half do we see?
Is any of this a shadow?
💬One sentence, then you move on
Why does tilt cause seasons when distance doesn't?
3Try one
Is there gravity where the space station orbits? Write yes or no.
I want a hint first
An orbit is falling around something and missing it. Without gravity there would be nothing to fall toward, and the station would fly off in a straight line.
💬Last one — then you're done here
Why isn't a moon phase the Earth's shadow?
Where this goes
Where this lives
Why it is dark when you walk home in December, why tides follow the Moon, and why a GPS satellite has to keep falling to stay up.
What this feeds
That is the last of the junior-high science rooms. High school picks the same ideas back up with more math attached.
Look outside tonight. What shape is the Moon, and where is the Sun from here?
One card at a time — tap “Show me” to check yourself, then Next. Start at Foundation; when those feel easy, climb.
Helpful Hints
🪜 From a day to a galaxy — the ladder
Rotation (a day) → revolution (a year) → tilt (the seasons) → the Moon’s orbit (phases, tides, eclipses) → gravity (every orbit) → the solar system (AU) → the galaxy (light-years).
Spin, circle, lean, Moon, pull, far, farther.
🤝 The whole topic in one idea
Everything we see in the sky is geometry plus gravity: where the Sun, Earth and Moon are relative to each other, and the pull that keeps them moving in circles. Draw the three bodies and the answer usually appears.
Where is the Sun? Where is the Moon? What is lit? What is in the way?
⚠️ Traps the test loves
Seasons are TILT, not distance. Earth is closest to the Sun in January.
Phases are NOT Earth’s shadow — that’s a lunar eclipse, and it’s rare.
New moon: Moon between us and the Sun. Full moon: Earth between. Don’t swap them.
A light-year is a DISTANCE.
There IS gravity in orbit — that’s what an orbit is.
The far side of the Moon gets sunlight. It just never faces Earth.
🌗 The Sun–Earth–Moon line-ups — the chart
Line-up
Phase
Eclipse possible?
Sun — Moon — Earth
new (we see nothing)
solar, if the line-up is exact
Moon at a right angle
quarter (half a disc)
no
Sun — Earth — Moon
full (whole disc)
lunar, if the line-up is exact
Between = new. Behind = full.
🎯 How the test will ask
A tilted Earth on its orbit — “which hemisphere has summer here?” (the one leaning toward the Sun).
A Moon position on a diagram — “what phase?” (how much of the lit half faces Earth).
A table of planet distances in AU — “build the scale model / which orbits fastest?” (closest orbits fastest).
“Why don’t astronauts fall?” (they do — they’re falling around Earth).
✅ Before the test, can you…
Explain the seasons with the word ‘tilt’ and the January fact?
Put the eight phases in order and draw the line-up for new and full?
Say why eclipses are rare in one sentence?
Turn a table of AU into a scale model with one multiplication?
Explain an orbit as falling and missing?
Pick your level
Look back at anything you missed — the hint that appeared is exactly what to reread tonight.
How sure did you feel?
Lab
Work like a scientist: label the diagrams, turn the table into a graph, then write a claim with evidence and reasoning. Every lab checks itself on the spot, and hints are free.
Your practice never leaves this device. There is no account and no sign-in. Your work is saved in this browser only, and you can erase it whenever you want.
Your practice record — saved on this device
This is your record of the module on screen — it stays here and goes nowhere. Independent means you got it right on the first tap; supported means you got it after the explain-and-retry, or marked ‘I had it’ on a revealed answer. Both count, and neither is a grade. If your teacher asks, copy the row or show them this screen.
Date
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Topic
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Level
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Independent
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Supported
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Hints used
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Cards studied
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Lab
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Traps met
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Explained in own words
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Confidence
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The answer key is for a teacher: it prints only from here, for the unit on screen. Print the study packet prints the study pages and a blank quiz — never the answers.