Chunk Stack
Word chunks fall down the well. Catch UN, then LOCK, then ED, and the wall spells unlocked. Miss, and the rubble piles up.
Play Chunk Stack — FreeFree · Ages 7+ · No account needed
How Chunk Stack Works
Hear the word, count the slots
The word is spoken and the build wall shows one empty slot per chunk — three slots for UN · BREAK · ABLE. You know how many pieces are coming; you have to work out which ones.
Catch the right chunk
Blocks fall carrying chunks. The one you need is always falling or in the next-three preview. Drop the right one and it flies to the wall. Drop a wrong one and it lands as rubble.
Keep the well clear
Finishing a word clears the tallest column of rubble; finishing one with no rubble at all clears the whole board. The round only ends if the rubble reaches the top.
Why Word Parts Beat Word Lists
A child who memorises words has to learn every word once. A child who sees the parts learns a few dozen pieces and can then spell thousands of words they have never been taught.
One root, a family of words
Port means carry. Once that lands, import, export, transport, portable and transportation stop being five spellings and become one root with five jackets on. Chunk Stack keeps returning to the same roots so the family becomes visible.
The near-miss pairs are the whole point
The decoy pieces are never random. They are the ones children actually confuse: -able against -ible, -ant against -ent, -tion against -sion, in- against im-. Picking between them is the decision that separates a speller from a memoriser.
Spelling changes shown, not recited
From level three the wall transforms as the piece lands — the silent e slides out of HOPE + ING, the n doubles in RUN + ING — and a one-line card names the rule. It never blocks play, and the links to the full rule wait until the round is over.
Slowness is never punished
There is no beat, no hit window and no timer on a decision. A block can sit at the top of the well while a child thinks. The only pressure comes from the rubble their own wrong answers leave behind, which is pressure they control.
The Three Rules Chunk Stack Teaches
Every spelling change in the game comes from one of these. Each has a full page of examples and exceptions.
The silent e rule
HOPE + ING drops the e: hoping. The e has done its job once another vowel arrives.
Doubling the final consonant
RUN + ING doubles the n: running. The extra letter keeps the vowel short.
Adding -ed and -ing
STOP + ED becomes stopped. The same two endings, and everything that happens to a word before them.
Frequently Asked Questions
What are prefixes, roots and suffixes?
Most long English words are built out of smaller parts. The root carries the meaning — lock, port, break. A prefix goes in front and changes that meaning: un- reverses it (unlock), re- repeats it (replay), pre- puts it first (preheat). A suffix goes on the end and usually changes the word's job in a sentence: -ing and -ed make a verb into a tense, -ful and -less turn a noun into a describing word, -tion turns a verb into a thing. Once a child can see those parts, a word like unbreakable stops being eleven letters to memorise and becomes three pieces they already know.
Why does the spelling change when you add -ing?
Because English protects the sound of the vowel in the root. Hope has a long o, held there by the silent e — and since -ing already starts with a vowel, the e is no longer needed and is dropped: hoping. Run has a short u, protected by a single consonant closing the syllable — so the n is doubled to keep it short: running. Without the doubling you would read runing with a long u. Chunk Stack shows the change happening on the wall, names the rule in one line, and links to the full explanation at the end of the round.
How is Chunk Stack different from other falling-block word games?
The falling piece is a whole chunk — two to five letters — not a single letter, and there is no music, no beat and no timing window. Nothing is ever judged on how fast you tap. The only question is whether the piece in the well is the next part of the word, and the only pressure is the rubble your wrong answers leave behind.
What happens if the right chunk isn't falling?
It always is, or it is in the next-three preview. The game guarantees the chunk you need is reachable without taking a wrong piece. If you would rather not wait, you can bin the current block — that costs one block of rubble pushed up from the floor. Deciding when a wasted block is worth it is the main strategic choice in the game.
What age is this game for?
Roughly ages 7 and up. The Starter band uses only un-, re-, -ing, -ed and -s and never changes a spelling at the join. Builder adds -ful, -less, -ly, -ness, pre- and mis-. Master adds -tion, -able, -ible, -ment and Latin roots like port, ject and spect, where the near-miss pieces are the classic traps: -able against -ible, -ant against -ent.
Is Chunk Stack free?
Yes. Three rounds a day with no account at all. A free account gives unlimited rounds and earns XP and streaks toward your child's dashboard.