Score: 0
ee: 0% READY
Time: 90
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About Chiral Cascade

Seed a chiral excess and ride the autocatalytic snowball to 99% enantiomeric excess in this free online chirality game about the Soai reaction and homochirality.

Chiral Cascade is an interactive stereochemistry game modeling asymmetric autocatalysis and the amplification of enantiomeric excess. Players manage a flowing racemic stream of left-handed and right-handed mirror-image molecules, seeding a small excess of one hand and shepherding the autocatalytic snowball toward 99% enantiomeric excess while racemization events flatten the mixture back toward 50/50.

The game faithfully simulates the Soai reaction, discovered by Kenso Soai in 1995. When a pyrimidine aldehyde substrate reacts with diisopropylzinc, the alcohol product formed is itself a catalyst for its own production. Each new product molecule recruits more achiral substrate into its own handedness, so a minuscule initial imbalance of just 1 to 2% can amplify exponentially into near-total enantiopurity. The mechanism is sharpened by heterochiral dimers: opposite enantiomers pair into catalytically inactive complexes, sequestering the minority hand and accelerating majority dominance. Racemase enzymes, UV photons and thermal racemization in the game mirror the real thermodynamic drive toward racemic equilibrium.

This discovery transformed how chemists think about the origin of biological homochirality, the deep mystery of why life uses only left-handed amino acids and right-handed sugars. The Soai reaction proved that stochastic tiny excesses, perhaps seeded by circularly polarized starlight or chiral quartz, could bootstrap to near-perfect purity without any external chiral influence. Asymmetric catalysis earned the 2001 Nobel Prize in Chemistry and remains essential for manufacturing single-enantiomer drugs, since the wrong mirror image of a medicine can be inactive or even harmful.

Key Science Concepts

What You'll Learn

Grade Level: High School, College

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How to play

  1. Seed the Stream Drag the probe over L or R molecules to empower them as glowing autocatalysts. Pick ONE hand and commit!
  2. Feed the Snowball Autocatalysts convert achiral precursors inside their aura. Every product is itself a new catalyst, so the majority grows exponentially.
  3. Defend Your Hand Racemase enzymes and UV photons scramble handedness back toward 50/50. Tap them before they erase your progress.
  4. Crack the Dimers L and R molecules lock into inert dimers. Tap them to crystallize out one of each hand and sharpen your majority.
  5. Refill Reagents Tap Zinc Reagent drops to flood fresh achiral substrate and recharge seed energy. Golden Soai stars burst-convert a huge area.
  6. Reach 99% ee Tap the ee gauge for a Soai Surge that pulse-converts precursors near every autocatalyst. Hit 99% ee to crystallize the batch!

Frequently asked questions

Is Chiral Cascade free to play?
Yes. Chiral Cascade is completely free to play in your browser. There is no download, install or account needed.
What grade level is Chiral Cascade for?
Chiral Cascade is designed for High School, College students and works well as a classroom activity or homework.
Does Chiral Cascade work on phones and tablets?
Yes. Chiral Cascade runs in any modern browser on desktop computers, Chromebooks, tablets and phones in landscape mode.

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