Smoke occurs when there isn’t enough oxygen

Wood is made from a combination
of water, hydrocarbons, and
minerals. As the temperature rises
above 149 degrees Celsius (300
degrees Fahrenheit), the hydrocarbons
start to vaporise, fl oating up into the
air. They combine with oxygen, burning
and releasing energy that is visible as a
hot fl ame. As they burn, they release
carbon dioxide and water vapour, both
colourless gases that you cannot see.
Sometimes there is not enough
oxygen for these evaporated
components to burn, and instead, they
continue to fl oat upwards, rising in the
hot air. The evaporated oils and tars
clump together as they rise, forming
fi ne particles known as smoke. The
particles move about randomly, and as
they collide with the invisible particles
that make up the air, they change
direction, producing the ever-changing
swirling patterns of smoke.
After all of these volatile
hydrocarbons have evaporated, all that
is left is charcoal, nearly pure carbon.
The charcoal does not evaporate, so as
it burns there is no fl ame, just glowing
embers. Once the charcoal is gone, all
that remains is ash, the minerals like
magnesium and potassium that do not
burn at all.