Question

our head does not crush despite it carries a weight of 100 kg air.

Answer 1

Human bodies are used to air pressure. The air pressure in our lungs, ears and stomachs is the same as the air pressure outside of our bodies, which ensures that we don’t get crushed. Our bodies are also flexible enough to cope when the internal and external pressures aren’t exactly the same. Aeroplanes need pressurised cabins to compensate for the lower air pressure at high altitudes. Despite this artificial atmosphere, the air pressure inside an aeroplane is not the same as at sea level. You might have noticed that if you drink from a plastic bottle during a flight and put the lid back on, when you land the bottle will be crushed. This is because the air in the bottle is at the lower pressure of the cabin and it can’t withstand the higher air pressure at ground level.

You’ve probably also noticed that your ears pop during the take off or landing of a flight. This is caused by the difference in air pressure on either side of your ear drums and the only way to equalise the pressures is to yawn, suck a sweet or breathing out whilst holding your nose.