080 EFFECT OF WAVELENGTHS OF LIGHT ON PHOTOSYNTHESIS

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080 EFFECT OF WAVELENGTHS OF LIGHT ON
PHOTOSYNTHESIS
Photosynthesis is performed by green plants using
carbon dioxide and water in the presence of
sunlight to produce sugar and oxygen. The quality
(wavelength) of light can have an influence on
the rate of photosynthesis.
MATERIALS REQUIRED
Beaker, Funnel, Test tube, Water, Razor blade,
cellotape (masking tape), Table lamp, Coloured
(red, yellow, green Blue) cellophane paper
(glass paper) Any small submerged aquatic plant
preferably Hydrilla.
Razor Blade
Funnel
Test tube
Hydrilla
cellotape
water
Table lamp
2
Transparent cellophane sheets as colour filters
3
Fill two-third of a beaker with water. Place the
Hydrilla in the beaker with an inverted funnel
over it and place a test tube in an inverted
position so that it covers the stem of the
funnel. Keep the set-up in a closed room near a
table lamp. The quality of light coming from
table lamp should vary using different cellophane
transparent papers. Care should be taken that no
other source of light should fall on the set up.
Photosynthesis will soon begin and the oxygen
released during the photosynthesis process can be
seen in the form of bubbles rising up in the
funnel stem. Note the time taken for the first
bubble to be released as well record the number
of bubbles released under each coloured filter
for a period of 20 minutes. Count and record the
number of bubbles released per minute in each
case. Discuss the variation observed under each
case.