Dancing flames. Glowing embers. Radiating warmth. Summer camping means time around the fire. While roasting marshmallows or listening to the guitar, let the flames ignite curiosity. What is fire? How does it burn? How hot is it?
Starting with the tinder, keep in mind the three essentials of fire: fuel, oxygen, and heat. Find the initial fuel: twigs, leaves, brown needles. Using the snap test, twigs must break easily, not bend. Wood must be dry, never green from the living plant.
Oxygen is essential for fire; it has to breathe. Stacking twigs in a cone-shaped teepee or square log cabin shape keeps air flowing as the kindling ignites. It might need more oxygen from blowing or fanning the flames, but too much air or wind and you lose the third essential: heat.
The fire catches and we add bigger branches and logs. Burning is a chemical process that breaks apart molecular bonds between carbon, hydrogen and oxygen atoms (wood is primarily these three elements) and produces light, heat, smoke, charcoal, soot and gases. Wood burning happens in two reactions: first, the heat breaks down molecules to form charred wood and flammable gases. Then, the gases combine with oxygen. This reaction emits light and heat and gases including water vapor, carbon dioxide (CO2), and carbon monoxide (CO).
My 5-year-old son is fascinated with the colors and heat of the fire (with endless comparisons to lava, dragon’s breathe and the sun). The flame colors are different temperatures with the shorter wavelength colors corresponding to more energy and heat (remember that light is a stream of particles that move in a wave pattern). In rainbow order, red – with the longest wavelength – is the coolest color; orange is hotter, followed by yellow hotter still. Blue is the hottest. White light is a combination of all the color wavelengths (including some blue); it’s slightly less energetic than the pure blue light.
As for the heat of the flames, reds are in the range of 1000-1800 degrees F (525-1000 Celsius). White flame is up to 2700 degrees F (2000 Celsius) and blue flames are above 3000 degrees Fahrenheit. (Can you smell the burning marshmallows?)
Enjoy the magic of summer campfires while respecting its power and potential. Know the local regulations, get permits, keep fire contained and put it out completely to keep everyone safe during this extra dry season.