How Does a Respirometer Work?

A respirometer calculates the oxygen uptake rate by displacing fluid in a glass tube connected to a sealed container. It includes a substance, such as soda lime pellets, to soak up the carbon dioxide given off. A respirometer is an instrument for measuring the extent of respiratory movement.

The oxygen uptake rate, or oxygen consumption rate, is the volume of oxygen consumed by the body in one minute. This rate is reported in liters or milliliters per minute at standard temperature and pressure, dry. Respirometers can be used to measure rates of metabolism by measuring the oxygen and carbon dioxide exchange. Respirometers can also be used to monitor other aerobic and anaerobic processes, such as biodegradation reactions to assist with cleaning up an oil spill, and to monitor the quality of treated waste-water.

A respirometer can be constructed with materials, including silicone rubber tubing, rubber bungs, a manometer, a scale, glass vials with stoppers and a substance to absorb the carbon dioxide. An equal volume of this absorbent substance should be prepared for each group in the experiment in separate vials with an airtight seal. These sealed vials must be given time to achieve equilibrium in the water to minimize volume changes due to changes in air temperature.