spirometers

• has an oxygen filled chamber with a moveable lid

  1. the person breathes through a tube connected to an oxygen chamber
  2. as person breathes in and out the lid moves
  3. can be recorded by a pen attached to chamber lid which writes on a rotating drum creating a spirometer trace
  4. soda lime in the tube the subject breathes in absorbs co2
• total volume of gas in chamber decreases over time, air thats breathed out is a mixture of o2 and co2