Firstly, we boiled 150ml of water in a beaker.
Then, we boil the leaf in the 100 degrees water for 2 minutes. This is supposed to break the cell structure(remove cell wall) in the leaf so the chlorophyll will not be unable to diffuse out of the cell due to the cell membrane and cell wall when coming out from the cell.
The leaf will look like its 'dancing in the water' due to convection currents.The hotter currents flow go up, while the cooler currents flow go down, thus forming a continuous cycle. The leaf thus appear to be blobs up and down due to these currents.
After 2 minutes, the bunsen burner was turned off and the leaf was placed into a 50ml beaker containing 20ml of alcohol.
The leaf was agitated(poked...as in non-scientific term) till the leaf was white (mostly).
Finally, the leaf was put into the beaker of hot water and was later put on a tile. A few drops of iodine solution was dripped onto the leaf.
The initial green part of the leaf turned from yellowish brown to blue black after dripping iodine solution on it, proving that the leaf had photosynthesized.
Under sunlight, the leaf, together with water and carbon dioxide, produced glucose and carbon dioxide. As the plant do not use up that much glucose, the excess sugar it produced is converted into starch. But why must it be converted into starch and stored ?
This is because glucose is easily soluble in water while starch is insoluble in water. So for storage in a plant cell, glucose is changed to insoluble starch. When the plant needs food it will simply be converted back to glucose.
Photos courtesy of Zhai Zihan, again.
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