Biology Core Practical Rate of Breathing

Investigating Breathing

Aim

To investigate tidal volume, vital capacity, rate of breathing, respiratory minute ventilation and oxygen consumption.

Research

(source 2)

Before performing spirometry, the equipment used must be calibrated. This is achieved using either a 3-L syringe that is pumped through to check that the meter is reading correctly (within a tolerance of 3%) or using a 1-L syringe that is pumped a litre at a time to a maximum of 7 L, which checks the linearity as well as the centre point of the volume measurement. (source 1)

We can calculate the ventilation rate from the spirometer which is, volume of air taken into the lungs in 1 minute. Ventilation rate = breaths taken per minute times tidal volume. (source 3)

The purpose of the soda lime canister (carbon dioxide absorber) is to absorb carbon dioxide so that the person does not breath in carbon dioxide.

Questions

Hypothesis

We will obtain valid results that will allow to measure tidal volume, vital capacity, rate of breathing respiratory minute ventilation and oxygen consumption.

Method

Set up the equipment shown in the picture (Source 2)

Run the spirometer software on a laptop and connect the spirometer to it

Attach the nose clip

Attach the breathing nozzle onto the spirometer and secure with sellotape

Place your lips around the nozzle

Look away from the screen and breath normally for 4 breaths followed by two forced breaths

Record the results and print them to work out the measures

Equipment list

• Spirometer – to record the breathing

• Laptop - to record the results using the breathing software

• Nose clip - to stop breathing through the nose

• Nozzles - to breath into

Variables

Independent variable - person doing the breathing

Dependent variables - tidal volume, vital capacity, rate of breathing respiratory minute ventilation and oxygen consumption.

Controlled variables - equipment