No. 344 · Fixing problems · Physics
Critical Mass
Many efforts only take off once they pass a threshold; below it, they fizzle out.
In the Almanac
“The Frisch–Peierls memorandum”, 1940 · “Tinder”, 2012
Both stories in full, three ways to use it and where it misleads.
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What is Critical Mass?
Critical Mass is the minimum amount of material needed to sustain a nuclear chain reaction. Below it, the reaction fizzles. Above it, the process feeds itself. The same is true of apps, communities, movements and habits: they need enough participants or repetitions before they keep going on their own.
How do you use Critical Mass?
To use it, concentrate before you expand. Build a small, dense circle of committed users, members or habits instead of a large, thin one. Win early adopters first and let them recruit the rest. And stay humble about where the threshold lies, because estimates can be badly wrong.
When does Critical Mass matter?
Critical Mass is one of the 40 mental models for fixing problems, the situations where you ask: Why does this keep going wrong, and how do I fix it for good? Within that, it belongs to “How problems spread”, alongside Broken Windows Theory, Chain Reaction and Containment.
What is an example of Critical Mass?
Two stories show it at work: The Frisch–Peierls memorandum (1940) and Tinder (2012). Both are told in full in The Mental Models Daily Almanac, which has two stories for each of its 365 models.
Which mental models are related to Critical Mass?
Tipping Point, Network Effects and Chain Reaction. Critical Mass itself comes from physics.