Hypothesis: The amount of sunlight there is affects how much starch is there in the leaf so I think the leaf with sunlight will have starch but the one without will not have any starch Variables: Dependent: Rate of photosynthesis (Use identical plants) Independent: Amount of sunlight given ( Put one under the sun and cover the other one with black plastic bag) Controlled: The conditions (Temperature, water, minerals, Humidity, light and controlling pest) We can manipulate them by putting the plants on the same place and using same so Uncontrolled: Weather, quality of equipments, Temperature of the room.
Materials (Apparatus): 1. 2 plants 2. Plastic bag 3. Beaker 4. Test tube 5. Lighter 6. Bunsen burner 7. Tripod stand 8. Wire gauze 9. Thermometer 10. Alcohol 11. Water 12. Iodine 13. Dropper Diagram Method Use two identical plants and put one of them with a lamp. 1. Cover one plant with black plastic bag. 2. Wait for several days. 3. Prepare all the materials needed for the experiment 4. Set up the equipments. 5. Take one leaf from the both plants. 6. Put the beaker filled with hot water on the wire gauze. 7. Turn the valve to open. 8. Light the lighter. 9. Open the gas tap.
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10. Put alchahol in two test tubes filled with alcohol. 11. Put each in the test tubes. 12. Wait until the leaves are discolored. 13. Hold the test tube using the test tube holder. 14. Take the leaf out using forceps. 15. Put on the white tile. 16. Using the dropper drop iodine onto the leaf to test for starch. 17. Observe the leaves whether they change color or not. Results The leaf that was given artificial sunlight, it turned into a purple-black color after the starch test which means that it contains starch. The one which did not receive sunlight did not have starch.
this shows that sunlight affects how much starch the leaf has thus my hypothesis is correct. Conclusion The plant that received sunlight got light had good minerals in the soil and was given enough water so it could photosynthesize and make starch. The one which did not receive sunlight had good minerals in the soil and was given water but because of no sunlight it did not photosynthesize and did not produce any starch. This shows that sunlight affects how much starch the leaf has thus my hypothesis is correct. Improvements The plant which did not receive sunlight was into a black plastic bag.
The plastic bag had a few holes which allowed light to go threw and there was a lamp close by and produced a lot of light this could have affected our results as the light would have threw the holes. The other improvement is that the Bunsen burner we were using was cheap quality so on Friday we did not finish the experiment so we had to take the leaf home and keep it in the refrigerator so the leaf could have some of its starch there and could have affected my results. The other bad thing is that the time it took for the water to start boiling because of the Bunsen burner the leaf could have lost some starch.
The other thing is that both of the leaves did not get the same amount of air as it was the atmospheres air they were depending on so it is not a very fair test and would have affected my conclusion. the alchahol we used while the experiment kept on evaporating of so every ten minutes it evaporated of so we had keep taking the leaf in and out which tore part of the leaf which only left a small amount of the leaf left for the starch test which is bad. The ayi switch off the lamp lights when it was end of school so this could affect our experiment.