How Does Atmospheric Temperature Affect Air Pressure?


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Temperature affects the lows and highs of air pressure but air pressure can also bring in higher or lower temperatures. The speed and movement of molecules is what determines air pressure.

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Proportionality of Temperature and Pressure
Atmospheric pressure and temperature are proportional, meaning that when the temperature increases, air pressure increases and when temperature decreases, air pressure decreases. The relationship between temperature and air pressure is referred to as Gay-Lussac's Law. It states that as long as the volume of an object remains the same than temperature and air pressure will always be proportionate. When temperature increases the molecules in the air begin to move at a faster rate. These quick moving molecules begin to hit the container or things within the atmosphere at a greater rate, increasing pressure. When the temperature decreases the molecules slow down and begin to bump into each other more and into atmospheric materials less, decreasing pressure. This would explain the science behind cooking foods in a pressure cooker, where the high temperature creates an extremely high-pressure situation as the molecules begin to smack rapidly into the cooker with no way of escape.

Air Pressure, Temperature and Altitude
Atmospheric pressure decreases the higher a person ascends into the atmosphere. As a person travels to a higher altitude the temperature will decrease at first but then begin to increase slightly. Energy levels change as a person gets closer to the edge of the atmosphere which is what causes the increase in temperature. Although there's an increase in temperature, the pressure decreases because the molecules begin to move faster. But without the constraints of pressure on the molecules, like there is at lower altitudes, the molecules continue to spread out further from each other, decreasing air pressure. This explains why atmospheric pressure is greater in low altitude places and lower in high altitudes like mountainous regions. This also explains why some people experience dizziness, headaches or blurry vision when at high altitudes because the change in barometric pressure affects bodily functions like blood pressure and blood thickness.

Air Pressure Affects Weather
In most cases high pressure means good weather and low pressure means poor weather. High pressure can prevent the formation of clouds, allowing for blue skies and clear, warm weather. Air cools as it rises and any moisture in the air can turn into rain or snow and fall back to the ground. This is why low pressure is associated with bad weather. Meteorologists use high and low pressure systems to predict the weather.

Temperature Affects Air Pressure in Tires
Air pressure changes within different containers depending on the outside temperature. A common example is tire pressure. The air pressure within a tire is actually what keeps a tire solid and helps it support the weight of a vehicle. When the temperature outside increases, the air pressure inside of a tire also increases. When outside temperature decreases, air pressure within a tire decreases. Most people will notice that cold winter temperatures lead to air pressure loss in vehicle tires or require more air fill ups when the temperature is at its' coldest. Hot temperatures make the tire pressure increase, and if the pressure increases too much is when a tire explodes. That's why race car tires are filled lower than an average car so that the air has room to expand when the tire temperature increases due to high speeds.

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