• UGI USER
  • Aug 07, 2024
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PRESSURE: ESSENTIAL PHYSICS IN EVERYDAY LIFE

Why in the news?

  • Pressure affects many aspects of daily life, from cooking with a pressure cooker to measuring blood pressure.
  • Understanding its physics reveals its impact, from atmospheric pressure to fluids in our bodies.

Understanding Pressure: Its Ubiquity and Significance

  • Microscopic Interaction with Pressure:
    • Pressure is the effect of countless atoms and molecules constantly hitting us, creating air pressure.
    • Examples include flight scenarios where reduced air pressure necessitates oxygen masks, and pressure cookers that use high pressure to cook food efficiently.
  • Pressure and Force:
    • Pressure is force distributed over an area. The unit of pressure is the pascal (Pa), with 1 Pa being very small.
    • For instance, a 100g apple exerts about 1 Newton (N) of force, translating to roughly 500 Pascals (Pa) on your hand.
source:wordpress
  • Blood Pressure and Measurement:
    • Blood pressure is measured in relation to atmospheric pressure, often using mercury in sphygmomanometers.
    • The reading of 120/80 mm Hg indicates pressure during heartbeats and resting phases, with mercury providing a practical measurement medium.
What is Pressure?

  • Definition: Force per unit area; measured in Pascals (Pa).
  • Example: A sharp knife exerts higher pressure than a blunt knife with the same force.

Types of Pressure:

  • Atmospheric Pressure: Pressure exerted by Earth’s atmosphere; measured with a barometer.
  • Fluid Pressure: Pressure from liquids/gases; measured with a manometer.
  • Buoyant Force: Upward force on submerged objects; Archimedes’ Principle.
  • Absolute Pressure: Pressure relative to a perfect vacuum.
  • Vapour Pressure: Pressure of vaporise liquid molecules in a closed container.
  • Blood Pressure: Pressure of circulating blood on vessel walls.
  • Surface Tension: Force minimising a liquid’s surface area.