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3.6 identify data sources, plan and choose equipment or resources to perform a first-hand investigation to gather data to determine the effect of light intensity and temperature on gas production in a suitable pond weed

identify data sources, plan and choose equipment or resources to perform a first-hand investigation to gather data to determine the effect of light intensity and temperature on gas production in a suitable pond weed

Sample method

For light intensity, set up several test tubes with fresh water and a suitable pondweed. Adding the same amount of NaHCO3 to each tube can ensure a good supply of CO2. Different light intensities can be produced by placing the test tubes at different distances from the same light source (a fluorescent desk lamp for example). Oxygen evolution can be determined using an oxygen sensitive probe and a data logger over time or bubbles of gas evolved per minute can be counted over time.