Strep throat Strep throat is a throat infection causing symptoms including a red sore throat with white patches. Hay fever Hay fever, an allergic reaction to outdoor pollens and molds, causes nasal congestion, itchy eyes, and more.
Air Density is the mass per unit volume of the air. For example, the standard air density at sea level is 1.225 kg/m 3 (0.076474 pounds/ft 3). Relative Density is the ratio of the actual air density to the standard sea level density, expressed as a percentage.
Lighter than air refers to materials (usually gases) that are buoyant in air because they have average densities lower than that of air. Dry air has a density of about 1.29 g/L (gram per liter) at standard conditions for temperature and pressure (STP), and an average molecular mass of 28.97 g/mol.