Give reasons: Paper by itself catches fire easily whereas a piece of paper wrapped around an aluminum pipe does not.

Paper itself catches fire easily due to its combustible nature and low ignition temperature. However, when enveloping an aluminum pipe, it becomes less prone to ignition for several reasons:

1. Heat Conductivity: Aluminum is an exceptional heat conductor. Wrapping paper around the pipe enables efficient heat dissipation, preventing the paper from reaching the critical temperature required for combustion.

2. Insulating Barrier: The aluminum surface acts as a protective barrier between the paper and potential heat sources, minimizing direct contact with sparks or flames that could ignite the paper.

3. Oxygen Restriction: Tightly wrapping paper around the aluminum pipe can limit the availability of oxygen, a crucial element for combustion, hindering the paper’s ignition process.

4. Surface Modification: Altering the paper’s surface area and thickness by wrapping it around the pipe changes its susceptibility to immediate ignition by reducing exposure to external ignition sources.

5. Protective Shield: The aluminum pipe serves as a shield, shielding the paper from direct contact with heat sources, offering an added layer of protection against rapid combustion.

In essence, the aluminum pipe, by dissipating heat, providing insulation, restricting oxygen, altering surface features, and acting as a protective shield, significantly reduces the likelihood of the paper catching fire compared to when it is exposed independently.