# Photosynthesis: Light and Plant

Topics: Light, Sunlight, Measurement Pages: 3 (727 words) Published: November 28, 2012
ESS Internal Assessment: Lab Report
Aim: The aim is to measure the rate of photosynthesis of an aquatic plant (Cabomba species) at different light intensities. Hypothesis: If the distance between the lamp and the plant increases the rate of photosynthesis decreases because the plant requires light for photosynthesis to occur. Variables:

Independent: The independent variable for this experiment is light intensity. In each trial the distance between the plant and the lamp will be increased, from 15 cm in the first trial to 30 cm in the second and then 50 cm in the third. Dependent: In this experiment we will measure the oxygen bubbles the plant releases into the water, per minute, to determine the rate of photosynthesis. Constant:

* The species of plant (Cabomba) and the specific plant specimen is going to be kept the soma throughout the experiment because most different species or specimens may photosynthesize at a different rate to others. * The amount of water was also kept constant

* The temperature of the water was kept constant at about 25 degrees Celsius (Room Temperature) as nothing was done to alter it throughout the experiment. * The time periods were also kept constant as we did three trials of five minutes each and always measured the amount of bubbles per minute. Method:

1. Add Sodium Bicarbonate to the water
2. Put plant in water
3. Put the lamp at 15 cm for the beaker containing the plant specimen. Make sure this is measure accurately 4. Light the lamp at the same time as the timer is started 5. Observe, count and document how many oxygen bubbles were released by the plant Materials:

1. Water
2. Sodium Bicarbonate
3. Lamp
4. Glass Vile
5. Funnel

Data Collection:

Measure| 15 cm| 30 cm| 50 cm|
1| 4| 3| 4|
2| 5| 5| 2|
3| 5| 5| 2|
4| 3| 4| 3|
5| 6| 1| 4|
Average | 4.6| 3.6| 3|

Discussion:
The results show, that on average, the further the...