Question

Why does a newspaper or stick lying in the open not catch fire on its own?

Answer 1

Hint: any substance or material will not catch fire on its own unless or until its temperature is less than the substance’s ignition temperature. Ignition temperature is defined as the lowest or minimum temperature required for any substance to catch fire.

Complete answer:
Combustion is a chemical reaction in which a substance combines with oxygen to produce heat. The substance which undergoes combustion is known as fuel.
For combustion, three things are required: fuel, heat, and oxygen. If any of these are not present then the combustion process will not take place.
The newspaper or stick acts as a fuel, oxygen is present everywhere but for any substance to catch fire it should get heat more than its ignition temperature than only it will catch fire.
Ignition temperature is the minimum temperature at which a substance needs to be heated so that it can catch fire below this temperature the substance will not catch fire on its own.
The newspaper or stick lying in the open has oxygen around it but it does not get heated up to its ignition temperature. Therefore a newspaper or stick lying in the open does not catch fire on its own.

Note:
We can control fire by removing or adding fuel, heat, and oxygen. The fire will go out if one of the three elements is removed. Weaken any one of them, and the fire will expire. Increase the intensity of the fire by increasing any one or more of the ingredients.