Simple Answer:
Warm air rises during convection. Perhaps better said, natural convection of air is the rising of less-dense warm air relative to the more-dense cold air.
This is a simple matter of buoyancy. Gravity pulls everything downward, but the pull is proportional to mass and items immersed in a fluid that have lower mass per unit volume than the fluid will tend to float, i.e. experience a buoyant force up as gravity pulls harder downward on the surrounding fluid.
Causes and Explanation:
Everyone says "Warm air rises" and that is an example of natural convection. Convection requires a fluid, heat source and gravity. The heat source causes a temperature gradient in the fluid so that buoyancy of the warmer fluid causes it to rise.
Buoyancy is the reasons bubbles rise and hot air balloons float and anything light, like a piece of wood, raises to the surface. The gravitational force experienced by a volume of material is just its weight, i.e. mass times gravity. Mass is the density of the material times its volume. So, if the object (like wood) has a lower density than water, the force of gravity on the object is less than the equivalent volume of water. The buoyant (upward) force is the difference in the wight of the object and the weight of the same volume of liquid.
Light objects experience the upward buoyant force and if the fluid (air or water or any fluid) is heated and expands, then it has a larger volume and less density and it also experiences the upward force.
The natural buoyancy of warmer fluids causes the force that moves the fluid and that movement is what we call natural convection.
Other Aspects:
Trachea
land breeze =D
Land Breeze
It will slow - sound moves faster in water than in air.
the diaphragm
Warm air is displaced by cooler denser air
The force that moves the continents is known as plate tectonics. This process is driven by the movement of Earth's lithosphere (the outer layer of the Earth) on top of the asthenosphere (semi-fluid layer beneath the lithosphere). It causes the plates to shift, leading to the movement of continents over millions of years.
Movement of air (and water) is all to do with temperature. Warm air (and water) rises, while cold air (and water) sinks.
Cool, dense air moves during night from the land toward water as = the answer is LAND BREEZE
Trachea
Air moves into the lungs when the diaphragm is flattened. The diaphragm is relaxed (arched) during expiration.
the diaphragm
because the air warms as it moves down
prevent each alveolus from collapsing as air moves in and out during respiration
Your diaphragm moves downward during exhaling.
Heat moves through liquids by the gases moving towards the convention.
how does the air around us moves?