A mule is a cross between a donkey and a horse. Therefore, a mule will have some donkey characteristics such as large ears, a head just a bit too large for its body, a skimpie â¦ r tail, some still have the cross on their backs from the donkey, and they often have small looking feet.
Density of air. The density of air, Ï (Greek: rho) (air density), is the mass per unit volume of Earth's atmosphere, and is a useful value in aeronautics and other sciences. Air density decreases with increasing altitude, as does air pressure. It also changes with variances in temperature or humidity.
Density. Density is the mass per unit volume. This means that the density of any solid, liquid or gas can be found by dividing its mass in kilograms by its volume in cubic metres. Density can be found using the equation: 1  The unit for density is kg m -3. 2  The density of water is approximately 1000 kg m -3 and air is approximately 1.3 kg m -3.his means that the density of any solid, liquid or gas can be found by dividing its mass in kilograms by its volume in cubic metres. Density can be found using the equation: 1  The unit for density is kg m -3. 2  The density of water is approximately 1000 kg m -3 and air is approximately 1.3 kg m -3.