The Effects of Various Wavelengths on Photosynthetic Rate
Photosynthesis is the process by which autotrophic organisms convert light
energy to chemical energy in the form of glucose [1]. Without this process life on earth
would be very different because every organism directly or indirectly depends on
photosynthesis. Because plants are at the bottom of the food chain they must create
their own energy; this is done through photosynthesis. Various pigments located
through out the leaves and stems of plants called chlorophylls absorb wavelengths from
sunlight. They absorb all wavelengths of natural light (400-700 nanometers), except
those between 525-550 nm which are reflected giving plants their green color [2].
The question of this experiment is how do different wavelengths effect
photosynthetic rate? The purpose of this experiment was to decide if blue light
(wavelengths of 425-475 nm) or red light (wavelengths of 650-700 nm) would produce
an increase in photosynthetic rate when compared to natural/white light (wavelengths of
400-700 nm). The hypothesis stated that the blue light would result in a higher
photosynthetic rate than the red light but both would be less than the control which was
white light. The rationale for this hypothesis is best depicted by Figure 1, which shows
the various types of chlorophylls and the wavelengths that they absorb [3]. It appears
that more absorption occurs around blue light than that of red light.
Due to classroom restrictions artificial light was used to conduct the experiment.
The classroom was necessary because a carbon dioxide sensor and computer were
used to calculate photosynthetic rate.
This research could be important if the results show outstanding increases in
photosynthetic rate. World Hunger is a major concern if a process could be found
through which photosynthetic rate is maximized perhaps food production could be
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