Which fuel will ignite more readily among the following?

• A. Log
• B. Kindling
• C. Newspaper
• D. Lumber

Answer: (C)

When a fuel is ready to ignite, two things matter most: how easily it reaches its ignition temperature and how much heat is exposed to the material. Materials with a lot of surface area relative to their mass and that are dry heat up and burn more quickly. Newspaper fits this best: it’s made of thin, dry sheets with a large surface area and very little mass, so a small flame or spark can raise it to its ignition temperature almost instantly. Logs and lumber are dense and heavier, often holding moisture, so they require much more heat and time to start burning. Kindling is designed to catch fire quickly, but given these options, newspaper commonly lights first because of its exceptionally favorable combination of low ignition energy and high surface-area-to-mass.