CP 10 - Factors affecting photosynthesis

Aim

Investigate the effects of light intensity, light wavelength, temperature and availability of carbon dioxide on the rate of photosynthesis using a suitable aquatic plant.

Equipment

• Pondweed

• Beaker

• Sodium hydrogen carbonate

• Aluminum foil

• Spatula

• Light filters

• Photosynthometer

• Paperclip

• Bench lamp

• Ruler

• Thermometer

• Stop clock

Method

• Place a piece of pondweed in a beaker of water.

• Cover one side of the beaker with the aluminium foil to block out the light.

• Cover the other side of the beaker with one of the light filters.

• Add sodium hydrogencarbonate in excess to the water to provide carbon dioxide.

• Leave for 5 minutes.

• Place the bench lamp a set distance from the beaker.

• Set up the photosynthometer. Leave for 5 minutes.

• Record the volume of gas produced during this time.

• Replace the filter with another colour of filter and repeat the experiment.

Rate of photosynthesis

Volume of oxygen produce/time