An experiment to investigate the effects of carbonate concentration in water on the rate of photosynthesis. Aim: The aim is to investigate how increasing carbonate in water can affect the rate of photosynthesis. Introduction: The rate of photosynthesis can be increased or decreased in many different ways. For example, by adding substances like alkaline or salt to the water, you can increase or decrease the acidity or basics, if the water has too much acidity, it can often delay the rate of photosynthesis, often stopping the rate of photosynthesis in the plant, which will possibly lead to killing the plant. Another option is to control the strength of the light by controlling the distance of the light from the plant. If the light is a far distance from the plant, the strength of light for the plant would be very weak, therefore decreasing the rate of photosynthesis.
Another alternate but simple way is to change the colored light by comparing different colored ﬁlters and their effects to change the rate of photosynthesis. Some colors like red and blue increase the rate of photosynthesis, while colors like yellow and green decrease the rate of photosynthesis. Many people would choose the factors that have just been listed, however there are so many other interesting possible factors when investigating other ways in which you can affect the rate of photosynthesis, Therefor, for this experiment the independent variable chosen is the amount of carbonate in water.
Hypothesis: Carbonate is known to increase the rate of photosynthesis when mixed with water, this is because plants inhale carbon dioxide which is what carbonate is made from along with other bases. By diluting carbonate in the water, this increases the amount of carbon dioxide in the water, which then increases the rate of photosynthesis, technically increasing the amount of bubbles within the experiment. However, too much carbonate might slow down the rate of photosynthesis within the plant. This is because, if too much carbonate is added within a small concentration of water with only one small plant, the amount of carbon dioxide released might be too overwhelming for one plant to handle, increasing the rate of photosynthesis to such a high extent can eventually make the plant loose itʼs energy to photosynthesize.
Apparatus/Materials • • • • • • • • • • • • • • Science apron Large Beaker (1000mls) Tap water Long wooden ruler(preferably 30cm) Scissors 12cm of fresh Elodea plant Large lamp- 60wat bulb Carbonate powder Mettle spoon/spatula Skewer Scale Paper stop watch book or laptop to collect data
Method 1. Find a clean, safe and flat working space to do your experiment, leave your workbook or laptop used to collect data on your working space 2. Put on a safety lab apron or coat 3. Grab all the equipment thats on the equipment list and place it on your working space 4. Take a large beaker(1000mls) and carefully fill it with 500mls of tap water 5. Place the large beaker on your working space, bend down at eye level in line with the water and check that the bottom of the waters meniscus curve is touching the ‘500mls’ point 6. If there is too much water, pour out some of the water into the sink, repeatedly doing step 3 to check if the measurement is correct 7. Turn on your lamp and make sure the bulb is 60 wats 8. Take your ruler and make sure the length distance between the lamp and the beaker is 1 cm, and make sure the height distance between the bulb and the beaker is 0 cm 9.
Take the Long wooden ruler (preferably 30cm) and some scissors to measure and cut 12cm of fresh Elodea plant 10. Turn on the lamp 11. Get ready your stop watch and your source used to collect data 12. Drop the 12 cm Elodea plant into the water 13. Quickly start the timer when you see the first bubble and record it in your data table for ‘Trail 1’ 14. When watching the plant, watch it from birds eye view(above the beaker) so that you can see the whole plant 15. Let the stop watch run for three minutes(1 minute for each trial) and record how many bubbles there are for each trial for each trial. 16. After finishing the three trials, if the plant floats to the top, push the plant down with a skewer 17.
For the next test, rip a section of paper thats about the size of your palm, place it on the scale 18. Turn on the scale 19. Take a spatula and the tub of carbonate powder and spoon some carbonate onto the paper that is sitting on the scale. 20. Keep on adding and taking away till you get 0.5 grams 21. Take the paper with the 0.5 grams of carbonate and pour it inside the water 22. Quickly stir the carbonate with a spatula so that it is fully dissolved into the water equally 23. Start the timer when your done stirring and repeat from step 14 to step 22
24. Once the data is finished collecting, add up the data for the 3 trials for the first test, divide the sum by 3 to get your average. Do this for a the rest of your tests till you get 5 averages for each of the 5 tests 25. Make a table on ‘Exle’, write test 1, 2 and so on in each cel and the amount of carbonate, then write the averages for each of the tests under 26. Highlight all of this then click whatever graph you think would be best Fair Testing Variables Independent variable Variable details Variables you will change Description • The Mass of carbonate powder increases by 0.5grams within each test • To Count the amount of bubbles released within each trial • Time frame for each trial 60sec • Distance in length and height between the lamp and the beaker is 0cm in height and 1cm in length. • Bulbs wattage-60wats • Mass of water in the beaker for every test is 500mls