The document describes an experiment to test how different variables affect the rate of photosynthesis in Elodea canadensis (Canadian pond weed). It was hypothesized that samples in tap water would produce more oxygen bubbles than those in distilled water, and that reducing the distance between the light source and plant would increase bubble production. The experiment found that plants in tap water produced more bubbles than in distilled water, and reducing the light distance from 20cm to 10cm nearly doubled bubble production, supporting the hypotheses. The experiment provided evidence that minerals in tap water and light intensity can influence photosynthesis rates.

3. 1 pair of scissors

4. 2 beakers

5. 1 stopwatch

6. 1 ruler

7. 1 pencil and paper to record dataMethod<br />Put on apron.<br />Pour the 125mL of distilled water into one beaker and the 125mL of tap water into the other beaker.<br />Using the scissors, cut the Elodea canadensis into two pieces, so that they each fit into the beakers.<br />Place one piece of Elodea canadensis each the beaker with distilled water.<br />Using your stopwatch, let the plant assimilate to the water for three minutes.<br />While these three minutes are passing, set up the lamp by plugging it in and turning it on.<br />Once the three minutes are up, stop the stopwatch, reset it and take the beaker with the distilled water and place it by the lamp.<br />With the ruler, measure out a 20cm distance between both objects and adjust the lamp so that the light is directed towards the beaker .<br />Start your stopwatch. For the first minute, let the pond weed again assimilate, this time to the light. Then, when the stopwatch reaches the one-minute mark, start counting the bubbles that the Elodea canadensis emits. After the remaining two minutes are up, stop counting and record your results.<br />Repeat steps 4 through 9, but this time using tap water.<br />Repeat steps 4 through 10, but this time the distance between the lamp and the beaker should be 10cm instead of 20cm.<br />Clean up after your experiment.<br />Design your method of presentation of data, and then record your final results.<br /> Raw Data<br />Table 1: showing the number of oxygen bubbles produced by Elodea plants in distilled water, tap water and NaHCO3 solution in a distance of 10 cm between the breaker and the light<br />TrialsH2O ( tap water)H2O (distilled water)NaHCO3 solution11921322242120mean21.52126<br />Graph 1: showing the number of oxygen bubbles produced by Elodea plants in distilled water, tap water and NaHCO3 solution in a distance of 10 cm between the breaker and the light<br />Table 2: showing the number of oxygen bubbles produced by Elodea plants in distilled water, tap water and NaHCO3 solution in a distance of 30 cm between the breaker and the light<br />TrialsH2O ( tap water)H2O (distilled water)NaHCO3 solution111184212197mean11.5190.5<br />Graph 2: showing the number of oxygen bubbles produced by Elodea plants in distilled water, tap water and NaHCO3 solution in a distance of 30 cm between the breaker and the light<br />Evaluation and Conclusion<br />By undergoing this investigation the hypothesis proves to be correct. This is clearly seen in the results of the experiment, such as in Table 1. While in the distilled water no bubbles whatsoever appeared, in the tap water the bubbles were so abundant that it became hard to count them. This is because minerals present in tap water such as magnesium act as catalysts when a plant undergoes photosynthesis. Also, when the distance between the light and the plant source was halved into 10cm, the bubbles almost doubled in amount. The intensity of light also proves to be an influencing factor in maximizing a plant's photosynthesis.<br />This experiment of course could be improved, by using a greater amount of water (the laboratory just happened to be running out of distilled water the day of the experiment), and using natural light as the light source and not a lamp. Also, more variables could be tested when it comes to water; carbon dioxide could be added to see what happens, and other kinds of ideas like this could be investigated. Lastly, more trials could be held to check the accuracy of the results. For the most part though, the aim of this investigation was accomplished.<br />Felix Dyrek<br />