ICSE Class 9 Answered
1. The aim of the experiment is to show that heat is evolved during respiration.
2. After few hours, the thermometer in flask A shows a higher reading, thus indicating a rise in temperature due to heat evolved by the germinating seeds. The thermometer in flask B does show any rise in temperature since no heat was evolved by the dead seeds.
3. Dilute formalin or carbolic acid is used to prevent bacterial growth in the flasks. If the bacteria grow, they would decay the seeds and thus, release heat which might interfere with the experimental observation.
4. A thermos flask prevents the loss or gain of heat energy due to conduction, convection, and radiation and thereby helps to obtain accurate observations.