Perform an experiment to see how different amounts of sunlight affect plants' photosynthesis. Get three small, potted plants of the exact same type. Put one in a dark place in your house, another in a place that gets light only a part of the day, and another that gets light almost all day. Be sure each plant has enough soil and a large enough pot. Water each plant at the same time with the same amount of water every day. Also every day, observe each plant and note the color, the height, and how droopy it is. Keep this up for a week. If all goes well, the plant with no sunlight will wilt, the one with some sunlight will be fairly weak, and the one in full sunlight will thrive. This shows that plants require sunlight for photosynthesis.
Focus your project on how the amount of water relates photosynthesis. Get three small, potted plants of the exact same type. Put all three in the same place, and make sure they all get lots of sunlight, have enough soil, and a large enough pot. Each day, water one of the plants fully, give just a little water to the second plant, and give no water to the third. Make and record your daily observations for a week. The plant with no water should wilt, the one with a little water will be fairly weak, and the one with all the water it needs will thrive. This shows that plants require water for photosynthesis.
Examine the link between carbon dioxide and photosynthesis. Again, get three small, potted plants of the exact same type. Put all three in different places, but make sure they all get lots of sunlight, have plenty of soil, and a large enough pot. Water each plant at the same time with the same amount of water every day. Also each day, talk to one of the plants for at least 15 minutes. You will be giving it more carbon dioxide than the others.Finally, make the same kind of daily observations as the previous experiments. Maintain this schedule for a week. The plant that has been talked to should do better than the other two. This shows that plants require CO2 for photosynthesis, and thrive when they get more of it.
Different plants process photosynthesis differently. Get three different potted plants. For example, one could be a small flower, another a larger vegetable plant, and a third could be a cactus. Just make sure you have a wide variety. Put all three in the same place, and make sure they all get lots of sunlight during the day. Follow the guidelines for soil and pot size from the previous steps.
Water each plant at the same time with the same amount of water every day. Make and record daily observations for a week.. The results show how different plants need different amounts of light and water. The cactus, for example, might do better with smaller amounts of water, while the other plants might not.