Practical: Is It Alive? Part 2

Task 3. How would you carry out an experiment to find out whether an unknown substance is a living thing?

Aim: To find out if the substance respires.

Equipments: a datalogger that can measure levels of oxygen and carbon dioxide in the surrounding, an air-tight container.


Procedure:

1. Measure the concentration of oxygen and carbon dioxide in the air-tight container using a datalogger.
2. Place the unknown substance in the container.
3. After 10 mins, measure the oxygen and carbon dioxide level in the container using a datalogger.
4. Repeat steps 1-3 to ensure reliability of the experiment.

Conclusion: If the oxygen level has decreased and the carbon dioxide level has increased, we can conclude that the substance is a living thing.