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Burn-Pattern Origin Explorer

Run the Burn-Pattern Origin Explorer MicroSim Fullscreen

About This MicroSim

A fire leaves its history written in scars. Hot gases climb up and out, so a flame scorches a wall into a V-pattern whose apex points down toward the origin — the lowest, most heavily damaged spot. The deepest, most concentrated char sits right on that origin.

This MicroSim gives investigators a top-down room plan where those cues are drawn but the origin is not marked. Your job is to read the evidence and place your own origin estimate, then check how close you got.

The strongest arson evidence is not one dramatic burn — it is the geometry. A single origin near an outlet is consistent with an accident. Two separate origins with no burn path connecting them is a strong arson indicator, because a fire cannot teleport. Either way, an accelerant claim still requires lab confirmation.

How to Use It

  1. Pick a Scenario: Accidental (single origin) or Suspicious (two origins).
  2. Study the V-pattern cones — each apex points toward an origin — and look for the deepest, most concentrated char.
  3. Drag the Fire spread slider to watch the char grow outward from the origin(s) as a time-lapse.
  4. Click the floor to drop your origin estimate.
  5. Press Score My Origin to see the distance to the nearest true origin and a rating: Excellent, Good, or Off. Toggle Show burn severity to reveal the full heat gradient and confirm your reasoning.
  6. In the two-origin scenario, watch for the MULTIPLE ORIGINS — arson red flag once the origins are revealed. Press Reset to try again.

Learning Objective

Analyze (L4): Locate a fire's point of origin from burn-severity evidence and flag multiple origins as an arson indicator. Investigators practice synthesizing V-pattern direction and char concentration into a defended origin call, and learn that two unconnected origins point to a set fire — a conclusion that still depends on lab confirmation of any accelerant.

You can embed this MicroSim on your own web page with this iframe:

<iframe src="https://dmccreary.github.io/forensic-science/sims/burn-pattern-origin-explorer/main.html"
        width="100%" height="570" scrolling="no"></iframe>

Lesson Plan

Audience: High-school forensic science (grades 9–12) Time: 15–20 minutes Bloom level: Analyze (L4) — locate a fire's point of origin and flag multiple origins as an arson indicator.

Warm-up. Ask investigators: "Fire moves up and out. If a flame burns a V-shaped scar into a wall, where on that V would you expect the fire to have started?"

Guided questions:

  • Using the V-pattern apex and the deepest char, place your origin estimate. What two cues did you combine, and how does the burn-severity overlay confirm or correct your call?
  • Run the Suspicious (two origins) scenario. Why are two separate origins with no burn path between them a strong arson indicator?
  • A single origin near an electrical outlet is "consistent with an accident." Why is that phrasing more careful than saying "this was an accident"?

Extension. Investigate how burn indicators can be misread (flashover, ventilation effects) and why an accelerant claim always requires laboratory confirmation of a residue sample.

References

Specification

This MicroSim was generated from a specification in Chapter 10: Fire Investigation, Arson, and Explosives.

Design note: the room, V-patterns, and char gradient are stylized for teaching — the spread model is a qualitative time-lapse chosen to make origin reasoning visible, not a physics-based fire simulation.