How to Master Decay Time
TLDR: Decay Time trains magnitude sense - the ability to distinguish weeks from decades from centuries. Build four anchor items (one per timescale layer), compare every new item to them, and watch the distractors tighten as your streak grows, forcing real intuition over lucky guessing.
What the Game Is Really Testing
Decay Time is a magnitude estimation game, not a trivia quiz. Each round shows an everyday item - a banana peel, a tin can, a plastic bottle - and four duration choices. Pick the closest one. One wrong answer ends your streak.
You won’t memorize that a tin can takes 50 years. Instead, you’ll build a mental timeline of how materials break down and learn to feel the difference between “months,” “decades,” and “centuries” as distinct categories. The durations come from environmental education tables (primarily NOAA marine-debris data) and are intentionally coarse - real decomposition depends on moisture, temperature, and burial conditions. The skill being trained is magnitude sense, not lab precision.
The game gets harder as you succeed. Early rounds give wide-gap distractors: “1 month, 5 years, 100 years, 1 million years.” You can guess and win. But at streak 10, 20, 30, the wrong answers close in. Now it’s “400 years, 450 years, 500 years, 600 years.” Guessing fails. You need genuine intuition.
The Four Timescale Layers
Anchor one item per layer. These four references do most of the work.
Fast layer (weeks to months): Banana peels, orange rinds, paper, cardboard, cotton socks. Biological materials in hospitable conditions. Think “a season” or “a school year.” All food peels land here. A paper bag decomposes in a few months.
Medium layer (years to a few decades): Wood, plywood, painted wood, leather, wool. Natural but tougher. Think “a human lifetime or less.” A wooden fence post lasts about a decade. Leather shoes outlast it by a few years.
Slow layer (50 to 200 years): Tin cans, aluminum cans, iron. Metals corrode steadily but stubbornly. Think “civilizations.” A tin can dropped today will be rust before your great-great-grandchild is born.
Glacial layer (centuries to forever): Plastic bags, plastic bottles, glass bottles, styrofoam. A plastic bottle lasts roughly 400-500 years. Glass can last a million. Styrofoam may never fully decompose. Think “geological.”
Two questions slot any item: “Is it biological or synthetic?” and “Hard or soft?” Biological and soft lands in the fast or medium layer. Synthetic and hard lands in the slow or glacial layer.
The four anchors: Banana peel (weeks), wooden stick (about a decade), tin can (50 years), plastic bottle (450 years). Compare every new item to one of these before looking at the choices.
Reading the Answer Choices
The choices tell you which layer the game is testing. Compare before isolating.
Early in a streak, one answer will be wildly wrong - bait. “1 month, 2 months, 5 months, 50 years” for a paper item - the 50-year answer is obvious bait. Choose from the tight cluster.
As your streak climbs, all four choices look plausible. This is when your anchor comparisons become essential. Ask: “Is this item more like a banana peel or a tin can? More like a tin can or a plastic bottle?” Compare to your four anchors, narrow to a layer, then pick within that layer.
Compare, don’t isolate: Never ask “How long does this material take?” in a vacuum. Ask “How long does this take relative to my four anchors?” Think in ratios, not absolute numbers. That’s magnitude sense - and it’s the only skill that keeps working when distractors close in.
Don’t memorize exact durations: Trying to memorize “a plastic bottle is exactly 450 years” is fragile and misses the point. Build intuition for the 400-500 year range. Know that plastic lasts much longer than metal, and metal lasts much longer than wood. Exact numbers shift by source and conditions - magnitude is what matters.
Playing the Categories
Decay Time lets you filter into three pools: full mix, nature and food, or human-made materials. Each keeps its own best streak.
Start with nature and food. These items decompose relatively quickly and follow clearer patterns. Paper, cotton, wool, food peels, wood. The timescales are forgiving: you’re estimating weeks, months, and years. Long streaks here build the foundation.
Advance to human-made materials. Here the game demands precision. Metals, plastics, and glass last decades to millennia. Wrong answers sit closer together. Being off by one order of magnitude (50 years vs 500 years) kills your streak. Your magnitude sense must be genuinely calibrated.
Full mix is the real test. You toggle between fast and slow layers constantly. One round you place a leaf (weeks), the next a glass bottle (a million years). This forces you to rebuild your mental frame each round, which is the hardest version of the skill.
Category progression: Build streaks of 20+ in nature and food before moving to human-made. Build streaks of 15+ in human-made before tackling the full mix. Skipping ahead produces lucky early wins and then a wall when distractors tighten.
Common Mistakes
Guessing without a model. Works at low streaks, fails immediately when distractors tighten. Before looking at any choices, run the two questions: biological or synthetic? Hard or soft? These two answers place you in a layer before you see the options.
Overestimating biological materials. New players consistently think paper takes years rather than months, or wood takes a century rather than a decade. Biological materials rot faster than intuition suggests, especially under moist or buried conditions. A paper bag is gone in a few months. A wooden plank lasts about a decade at most.
Underestimating plastics and glass. Synthetic materials last far longer than intuition suggests. A plastic shopping bag outlasts a car by centuries. Glass outlasts recorded human history. If an item is plastic or glass, your first instinct is almost certainly too short.
Confusing “looks intact” with “hasn’t decomposed.” Decomposition means “returns to natural elements,” not “turns to visible dust.” A plastic bottle buried for 50 years may look intact but is already fragmenting into microplastics. The 450-year figure is about full molecular breakdown, not visible disintegration.
After each loss: Spend 10 seconds asking where you would now place the item on your mental timeline. What made you pick the wrong layer? Reflection immediately after a miss matters more for retention than any amount of pre-study.
Practice Routine
Week 1 - Learn the layers. Play only nature and food. Identify the pattern: all food peels are weeks, all paper is months, all wood is years. Build your four anchors. Don’t move to human-made until this feels automatic.
Week 2 - Test the slow layer. Switch to human-made materials. Play 10-20 rounds daily. Feel the gap between metals (decades) and plastics (centuries) and glass (geological). The gap needs to feel visceral, not intellectual.
Use real objects as anchors: Hold a plastic bottle and a tin can while mentally placing them on the timeline. Physical interaction with the objects you’re estimating makes the timescale gap feel real in a way that abstract numbers don’t. The bottle in your hand takes 450 years to vanish. The can takes 50.
Week 3 - Mix and sharpen. Play the full mix. Your job now is smooth switching between timescales. When you fail, review the item and ask how your anchor comparison broke down. Adjust the anchor.
Ongoing - Chase long streaks. Once solid across all three categories, play for streak length. Aim for 50-round streaks. These require flawless speed plus genuinely calibrated intuition on tight distractors. They’re the real test of mastery.
Keep your four anchors active: Banana peel (weeks), wooden stick (decade), tin can (50 years), plastic bottle (450 years). Every wrong guess, trace back to which anchor you should have used. Did you compare against the wrong one? Did you land in the right layer but pick wrong within it? Different errors need different fixes.
Coasting after a long streak: Once you hit a comfortable streak (say, 20 correct), distractors are already tightening. If you’re not improving your model, you’re drifting toward a miss. Active reasoning on every round - not habit - is what extends long streaks.
Why This Matters Beyond the Game
Decomposition timescales shape environmental policy, recycling decisions, and waste management. When you intuitively feel that a plastic bottle lasts centuries, “just throw it away” stops being a coherent thought - there is no away. Your waste persists far longer than any human institution.
More broadly, magnitude sense is a transferable cognitive skill. Once you can move fluidly between timescales from weeks to millennia, the same mental agility applies to other orders of magnitude: populations, distances, costs, energy use. Decay Time builds it through play - a domain concrete enough to anchor the skill, wide enough in scale to stretch it.
The payoff: Genuine intuition for how long materials persist, a sharper general sense of orders of magnitude, and the ability to compare across wildly different scales quickly and accurately.
Decay Time
How long until it is gone? Guess how long everyday things take to decompose · from banana peels to glass bottles
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