Natural draft is a method of moving air or gases through a space without the use of mechanical fans. It relies on the natural buoyancy of warm air, which rises and creates a pressure difference. This difference allows cooler air to enter from lower areas, facilitating ventilation in buildings, chimneys, and other structures. In systems like chimneys, natural draft is essential for removing smoke and gases from fireplaces or stoves. The effectiveness of natural draft depends on factors such as temperature differences, the height of the chimney, and the design of the ventilation system, ensuring a steady flow of air.