Role of science in our everyday life: How air pressure affects breathing, cooking, blood pressure, driving and flying
--
Breathing:
Altitude and air pressure are closely related. It is well known that as we go up higher the atmospheric pressure decreases. There are two reasons for decreasing air pressure at higher altitudes. Firstly, due to earth’s gravity, it pulls the air molecules as close to the surface of the earth compressing them to increase pressure at lower altitudes than at higher altitudes and secondly, as altitude increases the amount of gas molecules in air decreases making them less dense and hence exerting less pressure.
Because of lesser gas molecules, it is also colder due to fewer chances of air molecules bumping into each other. Also, due to lesser gas molecules, there is lesser oxygen at higher altitudes. This explains why it is difficult to breathe at higher altitudes and the lungs have to work extra harder to deliver oxygen to the blood. But people already living at higher altitudes have developed more efficient lungs and other adaptations due to natural selection to cope up with this challenge.
Thus the bottom line is, as:
Altitude increases, Pressure decreases, air molecules decreases, oxygen decreases, affecting breathing.
Cooking:
With decreasing pressure at higher altitudes the boiling point of water also decreases. Boiling point is directly proportional to the atmospheric pressure. Let’s say, Water boils at 100 ℃ at sea level which means adding more heat would not increase the temperature of the water anything more than 100 ℃. It stays at 100 ℃ or can vaporize and leave as the vapor pressure of water becomes greater than atmospheric pressure.
At high altitudes, lower pressures causes the boiling point of water to decrease less than 100 ℃, say 95 ℃. This decrease in boiling point corresponds to lesser temperature and it takes more time to cook using water. The high altitude cooking problem can be mitigated by a pressure cooker. Pressure cooker uses the pressure principle by elevating the boiling point, say for more than 100 ℃ for water and hence more temperature can be added to make food cook faster…
