2.39: Practical: Investigate the Evolution of Carbon Dioxide and Heat from Respiring Seeds or Other Suitable Organisms

INVESTIGATING EVOLUTION OF CARBON DIOXIDE

Diagram showing the use of Respiring Organisms to Investigate Carbon Dioxide Production

METHOD: One end of a capillary tube is attached to a flask of Sodium Hydroxide to allow the inflow of air (inlet pipe) This flask is connected by a capillary tube to a flask of Hydrogen Carbonate (indicator A) This flask is connected by a capillary tube to a flask of respiring organism (e.g worms) This Flask is connected by a capillary tube to a flask of Hydrogen Carbonate (indicator B) Lastly, one end of a capillary tube is attached to this flask to allow the outflow of Air (outlet pipe)

RESULT: As air enters the first capillary tube, Sodium Hydroxide will absorb and remove Carbon Dioxide, therefore causing Hydrogen Carbonate indicator to turn red (indicator A) As air (deficient of Carbon Dioxide but abundant in Oxygen) enters the flask of respiring organisms, organisms will respire aerobically to produce Carbon Dioxide as waste product, therefore causing Hydrogen Carbonate indicator to turn Yellow (indicator B) This hence shows the production of Carbon Dioxide by living organisms, showing the evolution of Carbon Dioxide

INVESTIGATING EVOLUTION OF HEAT

Diagram showing the Use of Thermo Flasks with Seeds to investigate the Evolution of Heat

METHOD: Two thermo flasks are set up - one with germinating seeds and another with boiled seeds Thermometer wrapped in cotton wool is added into each thermo flask; cotton wool prevents the loss of heat Thermometer is used to measure and record the initial temperature in both thermo flasks After a fixed number of days, thermometer is used to measure and record the final temperature in both thermo flasks

RESULT: As germinating seeds are alive, they will respire aerobically to produce energy in the form of heat, therefore causing temperature of thermo flask to increase after the fixed period of time As boiled seeds are dead, they will not respire and therefore will not produce heat energy, causing temperature of thermo flask to remain constant after the fixed period of time Hence, this shows that living organisms respire to release energy in the form heat, therefore showing the evolution of heat