Question

Carry out the following osmosis experiment:
Take four peeled potato halves and scoos each one out to
make potato cups. One of these potato cups should be made
from a boiled potato. Put each potato cup in a trough
containing water. Now,
(a) Keep cup A empty
(b) Put one teaspoon sugar in cup B
(c) Put one teaspoon salt in cup C
(d) Put one teaspoon sugar in the boiled potato cup D.
Keep these for two hours. Then observe the four potato cups
and answer the following:
(i) Explain why water gathers in the hollowed portion of
B and C.
(ii) Why is potato A necessary for this experiment?
(iii) Explain why water does not gather in the hollowed out
portions of A and D.
​

Answer 1

Answer:

(i) Water gathers in the potatoes B and C because the potato acts as a semipermeable membrane as the concentration of water inside the cells is less than the outside i.e. the sugar and salt cells give out water to balance the concentration through OSMOSIS.

(ii) It is necessary to keep potato A empty to show that osmosis will not occur until there is a substance for the concentration to compare it.

(iii) Water does not gather in cup D because it is boiled, boiling damages the proteins of the plasma membrane. So, osmosis can't occur in this case.

Hope this will help you