Experiment to show that CO2 is evolved during respiration

Experiment to show that CO₂ is evolved during respiration:

Requirements: A round bottom flask with a cork,glass tube, flower petals, mercury, caustic potash, forceps, cotton, a stand with clamp.

Procedure: Let us put some fresh petals in a roundbottom flask, two-piece of caustic potash is introduced into the flask and then some cotton also introduced in to the neck of the flask. Then a cork having a central hole is fitted to the mouth

Procedure:  A  sieve  is  filled  with  saw  dust. Four  germinating  gram  seeds  are  placed towards the bottom of the sieve. The sawdust is moistened with water. The sieve then placed a little above the soil surface by supporting from either side of the sieve. The experimental set is then kept for observation.

Observation: After a day it will be seen thatroots from the seeds come out through the perforation of the sieve (due to geotropism) but again they bended and entered into the sieve.

Conclusion: As the sawdust in the sieve was wet with water, thus the roots ofthe seedlings re-entered into the moistened sawdust through the perforation of the sieve.