Simple Respirometer

This simple respirometer apparatus is designed to compare the rate of gas absorption or evolution in small organisms and microorganisms, such as insects, germinating seeds, or yeast. It provides a clear, practical way to investigate respiration and gas exchange in NCEA biology courses.

The apparatus consists of two stoppered boiling tubes connected by three-way taps to either limb of a graduated manometer. One tube holds the organisms and includes a syringe to adjust the liquid level during setup, while the second tube acts as a control thermo-barometer. During respiration, carbon dioxide produced by the organism is absorbed by potassium hydroxide in the experimental chamber, resulting in a measurable change in liquid level within the manometer. This allows students to directly observe oxygen uptake and calculate respiration rates with accuracy and confidence.

Key Features

• Measures rates of oxygen uptake or gas evolution during respiration
• Graduated manometer allows clear visual measurement of pressure change
• Two-chamber system with control thermo-barometer for accurate comparison
• Three-way taps enable precise adjustment during setup
• Includes wire baskets for supporting organisms safely
• Ideal for demonstrating effects of temperature and other variables on respiration rate

Specifications

• Application: Measurement of respiration and gas exchange
• Structure: Two stoppered boiling tubes connected to graduated manometer
• Adjustment: Syringe for liquid level calibration
• Suitable organisms: Insects, small invertebrates, germinating seeds, yeast
• Type: Classroom respirometer apparatus