# Doubling time
## MicroSim spec
- **Recommended sim type:** growth & decay
- **Microsimmability score:** 84/100
- **Layout:** drawing region (canvas) on top; control region (sliders/buttons) below.
### Parameters (tunable controls)
- `Growth rate`
- `Initial value`
- `Time span`
### What animates
A growing quantity repeatedly doubles, with the doubling interval shrinking as the rate rises.
### Learning objective
Relate doubling time to the growth rate of an exponential process.
## Links (Wikipedia order)
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`Albert_Allen_Bartlett` · [[Alexander_Bogdanov]] · [[Allenna_Leonard]] · [[Anatol_Rapoport]] · [[Anthony_Wilden]] · `Assyria` · `Babylonian_mathematics` · [[Barbara_J._Grosz]] · `Binary_logarithm` · [[Biological_system]] · [[Béla_H._Bánáthy]] · [[C._West_Churchman]] · `Cancer` · [[Charles_A._S._Hall]] · `Chelsea_Green_Publishing` · [[Claude_Shannon]] · [[Complex_system]] · `Compound_interest` · `Consumption_(economics)` · [[Control_theory]] · [[Coupled_human–environment_system]] · [[Cybernetics]] · [[Donella_Meadows]] · `E-folding` · `E_(mathematical_constant)` · [[Earth_system_science]] · `Economic_system` · [[Ecosystem]] · [[Edsger_W._Dijkstra]] · [[Edward_Norton_Lorenz]] · [[Eric_Trist]] · `Exponential_decay` · `Exponential_growth` · [[Francisco_Varela]] · `Fred_Emery_(psychologist)` · [[George_Dantzig]] · [[George_Klir]] · [[Gregory_Bateson]] · [[Half-life]] · [[Heinz_von_Foerster]] · [[Howard_T._Odum]] · [[Humberto_Maturana]] · [[Ilya_Prigogine]] · `Inflation` · [[Information_system]] · [[James_Grier_Miller]] · [[James_J._Kay]] · [[Jay_Wright_Forrester]] · [[Jennifer_Wilby]] · [[John_Seddon]] · [[Kathleen_Carley]] · [[Katia_Sycara]] · `Kenneth_E._Boulding` · [[Kevin_Warwick]] · [[Limiting_factor]] · [[List_of_systems_sciences_organizations]] · `List_of_systems_scientists` · [[Living_systems]] · [[Ludwig_von_Bertalanffy]] · [[Lydia_Kavraki]] · [[Manfred_Clynes]] · [[Manuela_M._Veloso]] · [[Margaret_Boden]] · [[Margaret_Mead]] · [[Mary_Cartwright]] · [[Mihajlo_D._Mesarovic]] · `Mike_Jackson_(systems_scientist)` · `Miriam_Lichtheim` · [[Multi-agent_system]] · [[Murray_Bowen]] · `Natural_logarithm_of_2` · [[Negative_feedback]] · [[Nervous_system]] · [[Niklas_Luhmann]] · [[Norbert_Wiener]] · [[Peter_Senge]] · [[Population_growth]] · [[Positive_feedback]] · [[Principia_Cybernetica]] · [[Qian_Xuesen]] · [[Radhika_Nagpal]] · [[Recommender_system]] · `Relative_growth_rate` · `Rule_of_72` · `Russell_L._Ackoff` · `Ruzena_Bajcsy` · `Social_system` · [[Sociotechnical_system]] · [[Stafford_Beer]] · [[Stephanie_Forrest]] · [[System]] · [[System_dynamics]] · `Systemics` · `Systems_analysis` · `Systems_art` · [[Systems_biology]] · [[Systems_ecology]] · [[Systems_engineering]] · [[Systems_neuroscience]] · [[Systems_pharmacology]] · `Systems_philosophy` · `Systems_psychology` · [[Systems_science]] · [[Systems_theory]] · `Systems_theory_in_anthropology` · [[Systems_theory_in_archaeology]] · [[Systems_theory_in_political_science]] · [[Systems_thinking]] · [[Talcott_Parsons]] · `Taylor_series` · [[Twelve_leverage_points]] · [[Urban_metabolism]] · `Victor_Aladjev` · [[Wayback_Machine]] · `World-systems_theory`
## From the Real GENERATIVE library (beauty pass)
*Doubling time — image hotlinked from Wikimedia Commons (via the Real G.E.N.E.R.A.T.I.V.E. course library, Engineering room). [Details & license](https://commons.wikimedia.org/wiki/File:Doubling_time_vs_half_life.svg).*
> The doubling time is the time it takes for a population to double in size/value. It is applied to population growth, inflation, resource extraction, consumption of goods, compound interest, the volume of malignant tumours, and many other things that tend to grow over time. ([Wikipedia](https://en.wikipedia.org/wiki/Doubling_time))
<!-- BEAUTY-PASS-MEDIA:END -->
> p5.js MicroSim stub · part of Systems Thinking · [Wikipedia source](https://en.wikipedia.org/wiki/Doubling_time)
> Relation: subfield of systems thinking.
## Concept summary
The doubling time is the time it takes for a population to double in size/value. It is applied to population growth, inflation, resource extraction, consumption of goods, compound interest, the volume of malignant tumours, and many other things that tend to grow over time.
## Build checklist
- [ ] Claim it: set `status: in-progress` + `lease` + `leased_at`
- [ ] Write the child page explaining the concept (tie it back to systems thinking)
- [ ] Finalize parameter ranges and defaults
- [ ] Implement the p5.js sketch (drawing + control regions)
- [ ] Add caption + the learning objective on the page
- [ ] Set `status: done`
## p5.js sketch
```javascript
// MicroSim: Doubling time
let controls = {};
function setup() {
// createCanvas(...); create sliders for the parameters above.
}
function draw() {
// background(...); read controls; render growth & decay; respond live.
}
```
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Back to Systems Thinking · Wikipedia: [Doubling time](https://en.wikipedia.org/wiki/Doubling_time)
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## Semiotic profile
> *The semiotic universals this article invokes, machine-derived from the crossref — **unverified** (born so). Populated 2026-07-06 for the Systems room.*
**Universals (4):** 🟡 system (15) · 🟢 exponential (10) · 🟡 science (5) · 🟢 saturation (2)
**Enter by sign:** Systems Semiotic Gateway · Alphabetum · Icon Registry · ← Systems Portal
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<!-- BEAUTY-PASS-MEDIA:START -->
## Wikipedia : Wikitube
**Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Doubling_time) : [Wikitube](https://en.wikitube.io/wiki/Doubling_time)
## Previous hub tags
Tree parents: [[Control_theory]] · [[Cybernetics]] · [[Operations_research]] · [[Reliability_engineering]] · [[System_dynamics]] · [[Systems_engineering]] · [[Systems_science]] · [[Systems_theory]].
Legacy hubs: none.
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*Sources: 3 legacy notes. Minted wave 1, 2026-07-30 (v1.6 order).*