The Effect of Chlorophyll on Visible Light
Stella C SA17EA
Lab partners: Alva P
and Filippa R
Aim: To investigate the effect of chlorophyll on visible
the chlorophyll solution turns out to be green then it will absorb all of the
colours in the visible light spectrum except green, which will be the only
colour remaining making green the colour on the whiteboard.
Background theory: Chlorophyll is a green pigment in plants which
absorbs energy from sunlight. Photosynthesis is the name of the process plants
use to convert sunlight, carbon dioxide and water to oxygen and glucose: Sunlight +
6CO2 + 6H2O ? C6H12O6 + 6O2
Chlorophyll allows plants to gain energy
through absorbing all other colours but green. The colours that are absorbed
contains energy, and is an important part of photosynthesis.
Therefore, an example from an everyday
event in nature can look like this;
Sunlight shines on a plant, which uses the
chlorophyll to absorb the colours in the visible light spectrum (except green)
leaving green to be reflected and for us to see. That is why plants are green.
Therefor it would be only logical if the light that shines through the solution
of chlorophyll will be green.
1. Plunge a leaf in boiling water for
about 1 min
2. After 1 min, chop up the leaf with
3. Put in the pieces in a mortar and grind
the leaf with a rich of sand
4. Add some acetone mixture and continue
grinding until you have a dark green liquid
5. Filter the liquid
6. Cover the filter with plastic
7. With the help of the teacher, shine a
beam of light onto the whiteboard.
8. Use a apprise to break the visible
light in its component parts.
9. Hold the chlorophyll between the light
+ the prism
10. Observe result
Safety: Hot water,
Volatile substances, alcohol/acetone – not good to inhale
Result: When we put the solution of chlorophyll between the
prism and the visible light, the visible light turned green.
Conclusion: The solution of chlorophyll turned green and therefore
the light on the whiteboard also turned green, since it absorbed all other
colours leaving green to be reflected, as our thesis stated.
Discussion: The results show the scientific relationship between
photosynthesis, chlorophyll, wavelengths and visible light. The relationship
between photosynthesis and chlorophyll is vital to carry out photosynthesis
since chlorophyll is needed to make carbon dioxide and water into oxygen and
glucose. When this happens there’s also a relationship between wavelengths and
visible light since the visible light in the plants are different wavelengths.
Their different wavelengths determine what colors we see which the results
show. The results show that we can’t see the red and blue wavelengths but we
can see the green wavelengths. This is because the red and blue wavelengths are
absorbed while the green wavelengths are reflected when the prism splits the
visible light into separate components and the chlorophyll is placed infront of
them. For example, we see a pair of jeans as blue because pigment in the fabric
absorbs the other colors, leaving only light in the blue part of the spectrum
to be reflected from the fabric to our eyes.The same rules apply when seeing
the green color from the clorofyll on the whiteboard – The pigment of the leaf
(clorofyl) absorbes all the other colors, leaving only lght in the green part
of the spectrum to be reflected from the board to our eyes.
A source of error: No color on the white
The leaf´s chlorophyll reaction depended
on how well the mixture, reacted. If one were to mortal the leaf not long
enough, the leaf wouldn´t be thin enough for the light to shine through the
chlorophyll. This could have resulted in no color on the whiteboard.
Mrs. Galleys lessons
The biology book pg. 107 – 111