Pressure in fluids

• What should you be able to calculate by the end of this video?

  The pressure of a fluid
• Why does atmospheric pressure decrease with an increase in height?

  Because the number of air molecules decreases
• What happens to a packet of crisps on an airplane?

  The packet enlarges due to pressure changes
• What are the characteristics of gas particles?

  They are widely spaced and moving rapidly
• What do gas particles do when they collide with the walls of a container?

  They exert a force at right angles to the wall
• What term do scientists use for gases and liquids?

  Fluids
• How do you calculate the pressure of a fluid?

  Pressure = Force / Area
• What is the unit of pressure?

  Pascal
• If a gas applies a force of 400,000 Newtons over an area of 8 m², what is the pressure?

  50,000 pascals
• Why do mountain climbers take oxygen supplies?

  Because air pressure is too low at high altitudes
• How does air pressure inside a packet of crisps compare to cabin pressure in an airplane?

  It is greater than cabin pressure
• What happens to the air pressure in the cabin of an airplane?

  It is kept at a slightly lower level
• What is the relationship between atmospheric pressure and altitude?

  • Atmospheric pressure decreases with height
  • Fewer air molecules above the surface
  • Greater density of air at ground level
• What are the key concepts related to pressure in fluids?

  • Pressure is force per unit area
  • Fluids exert pressure in all directions
  • Atmospheric pressure varies with altitude