Explaining Everything ™ on Instagram: "a chimney works using principles of convection and air pressure, often called the stack effect. The Mechanics of a Chimney Hot Air Rises: The fire within a fireplace heats the air and gases, making them less dense than the surrounding cooler air. This natural buoyancy causes the hot air to rise up the vertical chimney passage. Pressure Difference (Draft): As the hot air and smoke rise and exit the top, a low-pressure zone is created at the base of the chimn