How to Describe the Relationship of Boyle's Law to Ventilation

Boyle's Law states that if we measure the volume and pressure of a gas, then the figure we get from multiplying pressure times volume will never change. In layman's' terms that means if we add pressure by squeezing the gas into a tighter space, the volume will go down. If the volume expands because the gas is placed in a large container, the pressure will decrease. This law has implications for ventilation, or breathing.

Instructions

• 1

  State Boyle's Law in simple terms. The volume of a gas goes up when pressure is decreased. To put it even more simply, air (a gas) has more pressure in a small space and less pressure in a large space.

• 2

  Describe the lungs as they expand. The expanded area increases the volume and decreases the pressure in lungs. Air flows from the higher pressure air around us to the lower pressure space in the lungs.

• 3

  Point out that the small tubes in the lungs take in oxygen and expel carbon dioxide. The lungs now have carbon dioxide that must be expelled.

• 4

  Describe how contracting the lungs makes them smaller. That means there is less volume for the gas, meaning more pressure, and it moves out of the lungs into the lower pressure atmosphere. This is exhaling.

• 5

  Summarize the relationship of ventilation to Boyle's Law like this: Because increased volume decreases pressure in a gas, the expanded lung creates more volume and low pressure, causing outside, higher-pressure air to move in. Contracting the lungs decreases the volume available for air, and this increases the pressure. The higher-pressure air moves out of the lungs, through the throat into the atmosphere. Breathing is controlling air pressure by expanding and contracting the volume of the lungs.