Stage 2 · about 9–12
Models and Patterns
Explain with a model, predict with a pattern.
Simulations with sliders, insight videos, varied practice.
All subjects at this stage
C
Chinese
Why did the writer write it this way?
- Tap the beat of a Tang poem A five-character line is read in beats 2 + 3 (often 2 + 2 + 1 or 2 + 1 + 2) and a seven-character line 4 + 3 (2 + 2 + 3); in 绝句 and 律诗 the rhyme falls at the end of the even-numbered lines, and line 1 may rhyme too. Try it
- Reorder and cut: writing is choosing Moving or cutting one paragraph changes what the reader feels first and what they remember; what a writer leaves out is a choice too. Try it
- Move a comma, change the meaning Punctuation is part of the meaning: it decides where the pauses fall, who is speaking and what is asked, so the same characters can say opposite things. Try it
- Pick the comparison: what does the reader see? A metaphor lends the reader features of a familiar thing: call the moon a 白玉盘 (jade plate) and they see round and bright, call it a boat and they see a thin curve; choosing what to compare to is choosing what the reader notices. Try it
E
English
Can this word be taken apart?
- Build a word from parts A long word is often a root with parts added: prefixes change the meaning (un- = not, re- = again), suffixes mostly change the word class (-ness → noun, -ful/-less → adjective, -ly → adverb). Try it
- Tenses on a timeline A tense marks where an action sits in time relative to now; English changes the verb (its form or its helping verb), while Chinese keeps the verb and adds words like 了, 正在 or 会. Try it
- You don't need every word Knowing most of the words is enough to follow a story; the unknown ones often explain themselves from context. Try it
- Can you count it in English? English sorts nouns into countable and uncountable as a grammar label, not by whether the thing can really be counted: chairs but furniture, suggestions but advice; uncountable nouns take no a or -s and use much, some or a container word (a piece of advice). Try it
- Which adjective goes first? When several adjectives stand before a noun they follow a usual order — opinion, size, age, shape, colour, origin, material, purpose — so a lovely big old wooden table sounds right and an old wooden big lovely table does not. Try it
S
Science
How do we explain what we cannot see?
- Solid, liquid, gas: the same particles Heating does not change the particles, only how fast they move and how far apart they are. Try it
- Why a long lever helps Weight times distance must match on both sides; a longer arm needs less weight. Try it
- Who eats whom, and where the energy goes Each step up a food chain passes on only about a tenth of the energy; the rest is used for living and lost as heat. Try it
- Where does the sugar go? Dissolved sugar breaks into particles too small to see, spread through the water; the scale shows the total weight does not change. Try it
- Can a coat keep ice cold? A coat does not make heat; it slows heat moving across it — so it keeps a warm body warm and a cold ice cube cold. Try it
- Why does the Moon change shape? Half of the Moon is always lit by the Sun; as the Moon goes round Earth in about a month, we see different amounts of that lit half. Try it
G
Geography
Why is it hot here and cold there?
- Why is summer hot? Seasons come from Earth's tilted axis (about 23.44°): it changes how high the noon Sun climbs and how long the day lasts. Distance barely matters — Earth is closest to the Sun in early January. Try it
- Why is it night in New York when it's day in Beijing? Earth turns 15° every hour, so every 15° of longitude is one hour of sun time; time zones round this to whole hours and follow borders. Try it
- Why is it cold on a mountain top? Air is warmed mostly by the ground below, and it cools by about 6.5 °C for every kilometre you climb. Try it
- Read a hill from its contour lines Each contour line joins points of the same height, so lines packed close together mean a steep slope and lines far apart mean gentle ground. Try it
- Why one side of the mountain is dry Wind pushes moist air up the windward side, where it cools and rains; the air that comes down the other side is dry and warming, so the leeward side lies in a rain shadow. Try it
H
History
How far away is the past?
- How long ago is long ago? Time has length: written history is a thin slice, and civilisations overlapped in surprising ways — Cleopatra lived closer in time to the Moon landing than to the building of the Great Pyramid. Try it
- Meanwhile, somewhere else… Civilisations did not take turns: around 500 BCE Confucius in China, the Buddha in India and the citizens of Athens were alive in the same few generations. Try it
- Why was writing invented? The earliest clay tablets from Mesopotamia mostly record goods, rations and accounts — writing began as a tool for keeping track, not for telling stories. Try it
- Dig down, go back in time Layers of soil pile up over time, so deeper usually means older — but a pit dug from above can carry newer things down, and a layer can be no older than the newest object in it. Try it
- Whose year is it? A year number is only a count from a chosen starting point: BCE/CE counts from one fixed year with no year 0, the 干支 cycle repeats every 60 years, and regnal years restart with each ruler — to convert you need an anchor that links them. Try it
C
Computing
How can we write fewer commands?
- Draw shapes with loops A regular shape with n sides is 'forward, turn 360°/n' repeated n times. Try it
- A picture is a grid of numbers A screen picture is a grid of pixels, and each pixel's colour is three numbers: red, green, blue. Try it
- A robot that checks for walls With 'if there is a wall ahead, turn; otherwise go forward' inside a loop, one short program can get through many different mazes it has never seen. Try it
- The card-flip trick: catching an error Add one extra card to every row and column so each has an even number of black sides; then a single flipped card shows up as the one odd row crossing the one odd column. Try it