---
title: "Nuclear Decay Simulation"
id: 76538
type: "computer_media"
slug: "nuclear-decay-simulation"
url: "http://localhost/computer_media/nuclear-decay-simulation/"
markdown_url: "http://localhost/computer_media/nuclear-decay-simulation.md"
published_at: "2026-11-11T08:02:28+00:00"
modified_at: "2026-11-11T08:02:28+00:00"
author: "David Anderson"
featured_image:
  url: "http://localhost/wp-content/uploads/2026/11/nuclear-decay-simulation-1.png"
excerpt: "Simulate a radioactive decay chain with virtual dice on a ZX80, pass by pass, until every atom is stable."
post_tag:
  - name: "Downloadable"
    slug: "downloadable"
    taxonomy: "post_tag"
    url: "http://localhost/tag/downloadable/"
  - name: "ZX80"
    slug: "zx80"
    taxonomy: "post_tag"
    url: "http://localhost/tag/zx80/"
model:
  - name: "Sinclair ZX80"
    slug: "zx80"
    taxonomy: "model"
    url: "http://localhost/model/zx80/"
indiv:
  - name: "S. Sanderson"
    slug: "s-sanderson"
    taxonomy: "indiv"
    url: "http://localhost/indiv/s-sanderson/"
genre:
  - name: "Science"
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media_type: "Program"
programmers:
  - name: "S. Sanderson"
    slug: "s-sanderson"
    taxonomy: "indiv"
    url: "http://localhost/indiv/s-sanderson/"
download_url: "https://archive.org/download/timex-sinclair-software-archive/Nuclear%20Decay%20Simulation%20%281982%29%28Sanderson%2C%20S.%29%28ZX80%29%28US%29%28Program%29.zip"
mediadate: "1982"
images:
  - url: "http://localhost/wp-content/uploads/2026/11/nuclear-decay-simulation-1.png"
  - url: "http://localhost/wp-content/uploads/2026/11/nuclear-decay-simulation-2.png"
article_media:
  - id: 52523
    title: "Nuclear Decay Simulation"
    type: "article"
    url: "http://localhost/article/nuclear-decay-simulation/"
media_type_tags: "Science"
license: false
---

# Nuclear Decay Simulation

A computer version of the classroom dice experiment for radioactive decay. Enter the number of generations (2 for a parent that decays straight to a stable isotope, up to 5 for a chain), the relative half-life of each generation as the number of faces on its die, and the starting number of atoms. Each pass throws a die for every atom and moves the ones that decay to the next generation, then prints the count in each.

Press NEWLINE for the next pass; the program stops with ALL ATOMS STABLE. The article suggests more than 200 atoms for a smooth graph.

Published in Syntax February 1982 ([Nuclear Decay Simulation](https://timexsinclair.com/article/nuclear-decay-simulation/)).

## Source Code

```
  10 DIM H(5)
  20 DIM A(5)
  30 PRINT "NUCLEAR DECAY SIMULATION"
  40 PRINT
  50 PRINT
  60 PRINT "HOW MANY GENERATIONS? (>1)"
  70 INPUT G
  80 PRINT
  90 PRINT "RELATIVE 1/2 LIFE (FACES ON DIE)"
 100 FOR I=1 TO G-1
 110 PRINT "GEN. (";I;") = ";
 120 INPUT H(I)
 130 PRINT H(I)
 140 NEXT I
 150 LET A(G)=0
 160 LET K=0
 170 PRINT "INITIAL NO. OF ATOMS?"
 180 INPUT A
 190 LET A(1)=A
 200 FOR I=1 TO G-1
 210 IF A(I)=0 THEN GO TO 280
 220 LET N=A(I)
 230 FOR J=1 TO N
 240 IF NOT RND(H(I))=1 THEN GO TO 270
 250 LET A(I)=A(I)-1
 260 LET A(I+1)=A(I+1)+1
 270 NEXT J
 280 NEXT I
 290 LET K=K+1
 300 CLS
 310 PRINT "PASS ";K
 320 PRINT
 330 FOR I=1 TO G
 340 PRINT "GEN. (";I;") = ";A(I)
 350 NEXT I
 360 IF A(G)=A THEN GO TO 410
 370 PRINT "NL TO CONTINUE"
 380 INPUT A$
 390 IF A$="" THEN GO TO 200
 400 STOP
 410 PRINT
 420 PRINT "ALL ATOMS STABLE"
```