An Investigation into how light intensity affects the rate of photosynthesis.

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An Investigation into how light intensity affects the rate of photosynthesis

The aim of this activity is to observe and justify how the amount of light intensity exposed to a plant affects the amount of photosynthesis the plant performs.

I am trying to investigate the affect of light intensity on photosynthesis on a plant.

My hypothesis is that as the light intensity on the plant increases, the photosynthesis the plant performs will also rise proportionally. However I also hypothesize that when a certain level of light intensity is reached, the rate of increase will itself decrease. At this point temperature may become a limiting factor, which there is no control of.

Light is needed along with Chlorophyll to create a chemical reaction so that this conversion can take place. Without light, this cannot happen, and chlorophyll, found in chloroplasts cannot convert water and Carbon Dioxide. The light comes as light energy and is converted into chemical energy to convert the water and C02 into Glucose and Oxygen, which is just a by-product.  Furthermore, because of this, the greater the amount of Light, the more conversion there would be taking place and the quicker it would take place. Because of a greater intensity of light, there would be a greater amount of chemical reaction in the same or smaller amount of time.  

However, a limiting factor is also needed to be seen. In this case it may be Temperature or Carbon Dioxide, as they are too needed to be in absence or in gain for the experiment to be seen as a success. Because of the bulb to be used in the experiment, a lot more heat is given out and will therefore limit the factor of photosynthesis. Sodium hydrogen Carbonate gives the plant carbon dioxide so it can use the gas to actually execute photosynthesis. It gives the Stomata the carbon dioxide when reacted with water, to help Photosynthesis. Because of this, there is a constant supply of Carbon Dioxide.

With all of this knowledge, it must also be recognized that respiration also takes place at the same time and respiration itself used up oxygen to create more carbon dioxide. Thus, the count of bubbles could be severely disrupted because of oxygen usage.

Because Elodea plant is water-based it must be kept is a full tank of water, or the intake of Carbon Dioxide will differ.

One of the main factors that will lead to anomalies is temperature. This will most likely be created heat by the lamp. There will therefore be a temperature, which the enzymes can’t endure and will die. They will not convert anymore. The molecules in the cells would move faster kinetically and come to a point where they die.

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During the experiment, I am going to need: -

  1. A desktop lamp and bulb
  2. A plant
  3. A ventilated environment
  4. A flask
  5. Water
  6. A meter rule
  7. Stop Watch
  8. Sodium Hydrogen Carbonate
  9. Spatula with spooned end

I will set up my experiment in the way shown.

Fair testing is very important, so the variables that are kept constant are Co2 levels. These   levels will be kept the same by making ...

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