Introduction
The fire triangle is critical to fire fighting and fire investigation. Fire professionals must understand what are needs to burn and how eliminating one leg of the fire triangle can extinguish are. Why do fire fighters use water to put out a fire? What leg of the fire triangle are they eliminating?
Just like a candle flame can leave a soot pattern on a ceramic tile, fire investigators look for these types of patterns on walls, furniture, and other parts of structures to help them determine the point of origin of the fire, or the location where the fire started. Knowing where are started helps investigators understand how it was caused.
Questions
- What are the three things a fire must have to burn?
Problem to be Solved
- Firefighters and fire investigators need to know basic fire science to both fight fires and to uncover the source of a burn.
Module
The Fire Triangle
Age Group
Middle School
Category
Fire Forensics
Materials
- Long reach lighter
- Pillar candle or small candle
- Metal/non-flammable pie pan or tray (not! plastic, paper, or wax coated material) – place candle in pan
- Metal/non-flammable pie pan or tray (not! plastic, paper, or wax coated material) with 1-2″ of water
- Aluminum foil pieces (2) 2 cm x 2 cm with small slit (1/2″) cut in the middle of one side
- Glass jar or drinking glass
- Small (5 cm x 5 cm) metal screen (non-flammable)
- Tongs to handle materials that are hot or briefly flaming – plastic/heat resistant coated handles
- Large screwdriver with plastic (non-heat conducting) handle
- Ceramic tile
- Xplorlabs video: Investigation 1
Summary
Using a candle, students conduct four experiments to limit one of each side of the fire triangle – oxygen, fuel, and heat - to understand the needs of fire. Then, using a metal screen, students look at a candle flame to observe combustion.