About Lesson
Practical Activity: To show that heat is produced during aerobic respiration
Requirements
- Bean seeds
- Disinfectant
- Vacuum flask
- Thermometer
Procedure
- Soak some bean seeds for a day and wash them in dilute disinfectant.
- Place the germinating seeds into a vacuum flask and set as shown in the diagram.
- Read off the initial temperature and record.
- Leave the vacuum flask in an inverted position for two days.
- Note the temperature change at the end of the two days.
Results and Explanation
- The process that was being investigated was respiration.
- The expected results is that there would be a rise in temperature because the germinating seeds were respiring releasing heat energy.
- The vacuum flask was used to prevent any heat loss from the flask or heat gain from the surrounding.
- The cotton wool was used instead of a rubber ring to allow diffusion of gases into and out of the flask.
- The seeds were disinfected to kill any bacteria and fungi on the seeds thus preventing heat production from their respiration.
- The vacuum flask was inverted to allow the heavier carbon (IV) oxide diffuse out of the flask and give room for lighter oxygen to diffuse in.
- A suitable control experiment for this is, is having used boiled seeds instead of live ones in the vacuum flask.