i need a experiment ...ans me
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DEMONSTRATION OF ENDOSMOSIS AND EXOSMOSIS:
1) Apparatus (things needed in the following experiment):
A few grapes and raisins with intact (fixed) stalks, water, 10% salt solution, petri dishes or a cup.
Case 1: Place a few raisins in water for about 5-6 hours. Raisins will swell up. The swelling can be due to the absorption of water from the petri dish or cup.
Case 2:In another petri dish or cup place a few fresh grapes, (or swollen raisins) and pour the 10% salt solution into the dish. After a few hours the grapes will shrink or shrivel which can be possible only when they have lost water to the salt solution.
In the first case, the Raisins have absorbed the water from the outside due to the presence of higher concentration of solute in them (leads to turgidity of the cell or sweeping up which is good for a plant cell). This a classic example of endosmosis.
In the second case, the grapes have lost water to the salt solution because salt solution is more concentrated than the sap present in the grapes (leads to flaccidity of the cells or shrunkness and harmful to plant cell as the contents will come out). Therefore, it is an example of exosmosis.
Some Precautions:
1) Grapes and Raisins should be intact with stalks otherwise the experiment will not work as they also need roots and stalk for absorption (as a medium for it).
2) The solution for exosmosis must be stronger than the sap concentration present in the Grapes as, if it is not, then the experiment fails and they will remain at a normal state.
1) Apparatus (things needed in the following experiment):
A few grapes and raisins with intact (fixed) stalks, water, 10% salt solution, petri dishes or a cup.
Case 1: Place a few raisins in water for about 5-6 hours. Raisins will swell up. The swelling can be due to the absorption of water from the petri dish or cup.
Case 2:In another petri dish or cup place a few fresh grapes, (or swollen raisins) and pour the 10% salt solution into the dish. After a few hours the grapes will shrink or shrivel which can be possible only when they have lost water to the salt solution.
In the first case, the Raisins have absorbed the water from the outside due to the presence of higher concentration of solute in them (leads to turgidity of the cell or sweeping up which is good for a plant cell). This a classic example of endosmosis.
In the second case, the grapes have lost water to the salt solution because salt solution is more concentrated than the sap present in the grapes (leads to flaccidity of the cells or shrunkness and harmful to plant cell as the contents will come out). Therefore, it is an example of exosmosis.
Some Precautions:
1) Grapes and Raisins should be intact with stalks otherwise the experiment will not work as they also need roots and stalk for absorption (as a medium for it).
2) The solution for exosmosis must be stronger than the sap concentration present in the Grapes as, if it is not, then the experiment fails and they will remain at a normal state.
Haezel:
Thanks!
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