Design an experiment to demonstrate that oxygen is needed for respiration
Answers
Requirements:
Germinating seeds, a test tube, mercury, KOH crystals, petri dish, etc.
Method:
The mercury is filled in the test tube up to the rim. Take a petri dish full of mercury and put the mercury filled test tube in the inverted condition with the help of thumb. The thumb is removed inside the petri dish. Now introduce some seeds (germinating or soaked) in the test tube with the help of a forceps. Let this apparatus be put as such for some time.
Observation:
After some time the mercury level in test tube goes down. Now introduce some KOH crystals in the above test tube. After a little while the mercury level will go up to the former position.
Explanation:
The lowering of mercury level in test tube indicates that some gas has been released by germinating seeds. Only CO2 gas may be absorbed by KOH crystals. We see that with the introduction of KOH crystals the level of mercury goes high, hence the seeds have released CO2 under the anaerobic conditions.