This resource includes 1 file
Classroom Investigation 02: Heat Transfer and Ignition Teacher Guide
This teacher guide supports teachers in facilitating a 5E investigation where students make observations about how thermal energy is transferred and how transferred heat starts fires. Students compare the surface to mass ratio of a block of wood and a toothpick, then compare how easily they ignite. Students then make observations about how different materials ignite and burn.
Context
Solids and liquids do not burn. Gases burn. Solids and liquids are broken down into simpler molecular compounds (a chemical change) by the effects of heat. These gases are the products of decomposition and that is what burns in a fire.
In a candle, how do we go from solid wax to gaseous fuel? The wax isn’t burning until we add heat from the lighter or match, and then the heat is consistently applied by the burning wick. The solid wax is fuel, but does not burn until heat is applied.
Many things are fuel and can burn – things around us every day like clothes, hair, carpeting, furniture, etc. If heat comes into contact at a fast-enough rate, solids can turn to gaseous fuel through pyrolysis.
Knowing that when heat is applied, solids and liquids can turn to gaseous fuels, we need to know how heat is transferred. There are three main methods of heat transfer: 1) conduction, 2) convection, and 3) radiation.
Questions
- How do fires spread?
- How do fires start?
Problem to be solved
- When we know how heat is transferred, we can better understand the fire scene.
- Knowing the ignition of different materials helps fire investigators understand/read a burn scene.
Be sure to explore the video showing this classroom investigation and related student guide.
