Is natural gas heavier or lighter than air?

Natural gas is indeed lighter than air. This characteristic is due to its composition, primarily methane, which has a lower molecular weight compared to the gases that make up air. Air is made up of about 78% nitrogen and 21% oxygen, which have higher molecular weights than methane. As a result, when natural gas leaks or is released into the atmosphere, it tends to rise rather than sink. Understanding this property is crucial for safety and ventilation considerations in building analysis, as it affects how gas dispersion occurs in indoor and outdoor environments.

Other choices may imply incorrect assumptions about the density and behavior of natural gas in relation to air. For instance, saying natural gas is heavier than air would misrepresent its behavior and could lead to improper safety precautions. Equal in weight would overlook the fundamental differences in molecular composition. Lastly, the idea that it depends on humidity is not relevant, as the density of natural gas relative to air remains consistent regardless of humidity levels.