What is CSEEL and what does it offer?

CSEEL (Center for Scientific Exploration and Experiential Learning) is a premier Indian STEM educational initiative offering hands-on science experiments, 3D live laboratory simulations, curriculum-aligned project kits, teacher training workshops, and national science conclaves aligned with NEP 2020.

How does CSEEL support NEP 2020 experiential learning?

CSEEL shifts education from rote memorization to active inquiry and hands-on experimentation. Students observe, build, analyze, and apply scientific concepts to real-world challenges, developing critical thinking and scientific temper as envisioned by NEP 2020.

What subjects and classes are covered in CSEEL simulations and experiments?

CSEEL provides comprehensive physics, chemistry, biology, environmental science, and applied robotics experiments and virtual simulations for students from Class 6 through Class 12, mapped to CBSE, ICSE, and state curricula.

How can schools, educators, and students access CSEEL programs?

Institutions, teachers, and students can explore live simulations, order DIY lab kits, register for national seminars, and join the CSEEL EduNetwork by visiting https://www.cseel.org.

Light & Starch Test for Photosynthesis in Variegated Leaves

Experiment video

What you will learn

Demonstrate that sunlight and chlorophyll are essential for photosynthesis using a destarched variegated Croton/Coleus leaf and the iodine-starch test.

Materials needed

Potted plant with variegated leaves (Croton / Coleus / Money Plant)
Potted plant with variegated leaves (Croton / Coleus / Money Plant)
₹50
What is it?
Lugol's Iodine biological reagent solution (I2 in aqueous Potassium Iodide KI).
Specifications
Composition
1 g Iodine + 2 g KI dissolved in 100 mL distilled water
Target
Specific starch amylose helical inclusion test (blue-black)
Bottle
Amber glass dropper bottle
Ethanol / Methylated Spirit (95%) mL
Ethanol / Methylated Spirit (95%) mL
₹95
What is it?
Potted Coleus or Money plant (Epipremnum aureum) with healthy variegated leaves.
Specifications
Plant Condition
Vigorous destarched potted foliage plant
Leaf Type
Variegated leaves with green chlorophyll center and white margin
Lugol's Iodine Solution (1% I2 in KI) dropper bottle
Lugol's Iodine Solution (1% I2 in KI) dropper bottle
₹140
What is it?
Laboratory water bath setup: 250 mL beaker, boiling tubes, 90% ethanol, and black paper masks.
Specifications
Solvent
90% Denatured ethyl alcohol AR
Paper Mask
Opaque black stencil paper with brass clips
Black opaque paper strip and paper clips set
Black opaque paper strip and paper clips set
₹185
What is it?
Standard laboratory apparatus used in Light & Starch Test for Photosynthesis in Variegated Leaves.
Specifications
Category
Biology Apparatus
Grade
CBSE / NEP 2020 Laboratory Standard
Water Bath (500 mL beaker with boiling water)
Water Bath (500 mL beaker with boiling water)
₹230
What is it?
Standard laboratory apparatus used in Light & Starch Test for Photosynthesis in Variegated Leaves.
Specifications
Category
Biology Apparatus
Grade
CBSE / NEP 2020 Laboratory Standard
Petri Dish and Forceps set
Petri Dish and Forceps set
₹275
What is it?
Standard laboratory apparatus used in Light & Starch Test for Photosynthesis in Variegated Leaves.
Specifications
Category
Biology Apparatus
Grade
CBSE / NEP 2020 Laboratory Standard
Bunsen Burner, Tripod, and Wire Gauze set
Bunsen Burner, Tripod, and Wire Gauze set
₹320
What is it?
Standard laboratory apparatus used in Light & Starch Test for Photosynthesis in Variegated Leaves.
Specifications
Category
Biology Apparatus
Grade
CBSE / NEP 2020 Laboratory Standard

Tick items as you collect them. Tap + to see the product, specifications and buy options.

Stay safe

Never heat ethanol directly over an open flame; always use a water bath (ethanol is highly flammable).
Destarching in complete darkness for a full 48-72 hours is crucial to ensure baseline negative starch.
Boil leaf thoroughly in alcohol until completely bleached so green pigment does not obscure iodine results.
Handle hot glassware with beaker tongs.

Steps

0 of 7 steps done

1Destarch the potted variegated plant by keeping it in a dark room for 72 hours (respiration consumes stored leaf starch).
Observation
Destarch potted plant by keeping in complete dark room for 48 hours to exhaust all stored starch from leaves.
Safety
Confirm destarching on a test leaf before proceeding with experimental setup.
2Clip a strip of black paper across a healthy leaf to block light in that region.
Observation
Attach black paper strip with paper clips across middle of an intact attached leaf; expose plant to bright sunlight for 6 hours.
Safety
Ensure paper clips hold black mask tightly on both top and bottom surfaces to block stray light.
3Place the plant in bright direct sunlight for 6 hours to allow photosynthesis to proceed.
Observation
Pluck leaf, remove paper strip, and boil leaf in water beaker for 2 minutes to kill protoplasm and rupture cell walls.
Safety
Use forceps to handle boiling leaves.
4Pluck the test leaf and sketch its green and non-green patterns on paper for reference.
Observation
Transfer leaf into test tube containing 90% ethanol; heat in water bath until leaf is completely decolored and bleached white.
Safety
NEVER heat ethanol test tube directly over flame; alcohol vapors ignite violently! Always use boiling water bath.
5Boil the leaf in water for 2 minutes to soften cell walls and denature enzymes.
Observation
Dip brittle bleached leaf in warm water to soften; spread flat in petri dish and flood with Lugol's iodine solution for 3 minutes.
Safety
Iodine stains skin and benches brown; wear disposable gloves.
6Transfer the leaf into a beaker of ethanol placed inside the boiling water bath until all green chlorophyll dissolves and the leaf turns chalky white.
Observation
Rinse with tap water: exposed parts turn deep blue-black while masked strip remains pale brown, proving light is essential.
Safety
Dispose of waste ethanol into dedicated organic waste carboy.
7Wash leaf in warm water to soften it, spread in a petri dish, add dilute iodine solution, and observe blue-black color development.

Tap + on a step to see what you will observe and any safety tips.

Record your observations

Leaf Area Sample	Condition during Light Exposure	Color after Ethanol Decoloration	Color after Iodine Staining	Starch Presence
Unmasked Green Area	Directly exposed to sunlight (6 hrs)	Pale creamy white / bleached	Intense Blue-Black coloration	Starch present (Photosynthesis occurred)
Black Paper Masked Strip	Completely shielded from sunlight	Pale creamy white / bleached	Pale Yellowish-Brown (Iodine color)	Starch absent (No light, no photosynthesis)
Variegated White Margin	Exposed to light but lacks chlorophyll	Naturally white / non-pigmented	Pale Yellowish-Brown (Iodine color)	Starch absent (Chlorophyll essential)
Variegated Green Center	Exposed to light and has chlorophyll	Pale creamy white / bleached	Intense Blue-Black coloration	Starch present (Photosynthesis occurred)

Tap a highlighted cell to write your own observation.

Result and conclusion

Only green chlorophyll-bearing regions exposed to light turn blue-black with iodine; white and light-blocked areas remain pale yellow/brown, proving light and chlorophyll are essential.

6 CO2 + 12 H2O + Light -> C6H12O6 + 6 O2 + 6 H2O; Amylose + I2/KI -> Polyiodide Inclusion Complex (Blue-Black)

Observation	What it means
Light Essentiality Proved	Area covered by black paper strip fails to form starch, proving sunlight is strictly necessary for photosynthesis.
Chlorophyll Requirement Proved	White margins of variegated Money Plant/Croton leaf produce zero starch despite full sunlight, proving chlorophyll is indispensable.
Decoloration by Boiling Alcohol	Ethanol extracts green chlorophyll into solution, unmasking pale leaf mesophyll so blue-black starch reaction is cleanly visible.
Amylose Iodine Inclusion Complex	Iodine slips into helical coils of amylose starch polysaccharide chains, yielding diagnostic deep blue-black charge-transfer color.

Starch Density Percentage across Differentially Exposed Leaf Sectors

Sample readings. Replace with your own results.

Experiment photos

Before the experimentDuring the experimentResult