The Effects of Light Intensity on the Rate of Photosynthesis
Aim: To investigate the effects of light intensity on photosynthesis. Background: Photosynthesis is a process that plants undergo to produce glucose. The plant then uses the glucose to produce energy which the plant needs to sustain life. The chemical formula for photosynthesis is: Sunlight 6CO2 +6H2O → C6H12O6 + 6O2
The plant requires light, carbon dioxide and water to partake in photosynthesis. Photosynthesis is crucial to the survival of the plant and all organisms that rely on the plant for food as it enables the plant to produce glucose which it uses to produce energy (ATP) to enable the plant to grow and survive. If one of these requirements were to be increased in quantity, then logically, the rate of photosynthesis in the plant would be increased as well due to the increased amount of resources. In this experiment, the requirement that was increased was light measured in the form of intensity. It is expected that light intensity will affect the plant’s rate of photosynthesis by increasing it due to the increased amount of resources that the plant now has. The rate of photosynthesis increases as light intensity is increased further; however, the rate of photosynthesis is eventually limited by some other factor. (Royal Society of Chemistry, no date)
Prediction/Hypothesis: The plants rate of photosynthesis will increase as the intensity of light is increased.
* One 1L beaker
* One test tube
* 500ml of distilled water
* One bench lamp
* One 1m ruler
* Stirring Rod
* 5 teaspoons of Sodium Bi-Carbonate
* Small Funnel
1. The sodium bi-carbonate was stirred with 500mL of distilled water in a 1L beaker. 2. The test tube was filled with the solution.
3. The Elodea was cut into a 10cm long piece.
4. The piece of Elodea was put into the wide part of the funnel. 5. The funnel was placed wide part down in the beaker full of the remaining solution. 6. In one swift movement, the test tube with the sodium bi-carbonate and distilled water solution in it was flipped upside down on top of the thin part of the funnel. If done correctly, the level of water should be near the top and above the top of the funnel. 7. The beaker was set up 1m away from the bench lamp in a dark place, using the ruler. 8. The set-up was left alone for two minutes to stabilise. 9. The number of oxygen bubbles produced by the plant was recorded for two minutes as they floated up to the top of the upside-down test tube. 10. The measurement was repeated three times at the same distance. 11. The beaker was moved closer to the lamp, to the distance of 75cm. 12. The set-up was left alone for two minutes to stabilise. 13. The number of oxygen bubbles produced by the plant was recorded for two minutes as they floated up to the top of the upside-down test tube. 14. The measurement was repeated three times at the same distance. 15. Repeat steps 11-14 for all distances until all results have been collected.
| Prevention or Emergency/Clean-Up Procedure
Ingestion of Sodium Bi-Carbonate
| As sodium bi-carbonate is only lethal if ingested in large amounts, awareness will be raised to those in contact with the substance however, it should be known that chemicals from the laboratory should not be ingested at all. If the substance is ingested, medical attention should be sought.
| Broken Glass
| To prevent broken glass in the first place, glass should only be handled with dry hands and using the correct grip. If glass is broken, it could cause injury if not properly managed. A teacher should be alerted and the glass should be carefully placed in the broken glass bin.
| Containers holding liquids should be handled with dry...
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