A<unk>  is a device used to measure the rate of respiration of a living organism by measuring its rate of exchange of oxygen and/or carbon dioxide. They allow investigation into how factors such as age, or chemicals affect the rate of respiration.<unk> s are designed to measure respiration either on the level of a whole animal or plant or on the cellular level. These fields are covered by whole animal and cellular (or mitochondrial)<unk> y, respectively. A simple whole plant<unk>  designed to measure oxygen uptake or CO2 release consists of a sealed container with the living specimen together with a substance to absorb the carbon dioxide given off during respiration, such as soda lime pellets or cotton wads soaked with potassium hydroxide. The oxygen uptake is detected by manometry. Typically, a U-tube manometer is used, which directly shows the pressure difference between the container and the atmosphere. As an organism takes up O2, it generates a proportionate quantity of CO2 (see respiratory quotient), but all the CO2 is absorbed by the soda lime. Therefore, all of the drop of pressure in the chamber can be attributed to the drop of O2 partial pressure in the container. The rate of change gives a direct and reasonably accurate reading for the organism's rate of respiration. As changes in temperature or pressure can also affect the displacement of the manometric fluid, a second<unk>  identical to the first except with a dead specimen (or something with the same mass as the specimen in place of the organism) is sometimes set up. Subtracting the displacement of the second<unk>  from the first allows for control of these factors. The set up of modern<unk> s is described in more detail under<unk> y. A<unk>  may also be called an oxygraph. Suppliers for whole animal<unk> s are e.g. Sable Systems,<unk>  Systems and Applications, Qubit Systems, Eco-environment, Bio-technology, or Challenge Technology; for mitochondrial<unk> s, Oroboros Instruments, Hansatech Instruments, or YSI.
Respirometer
Spirometer
Gaseous detection device
Air ioniser
Carbon monoxide detector
Respiratory pressure meter
Air purifier
Breath diagnostics