Question

Take four peeled potato halves and scoop each one cut 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 of sugar in cup B.
(c) Put one teaspoon of salt in cup C.
(d) Put one teaspoon of sugar in the boiled potato cup D.
Keep these for two hours. Then observe the four potato cups and answer the following.

Explain why water gathers in the hollowed portion of cup B and cup C.

Answer 1

In potato cup B and C that contains sugar and salt respectively, the water concentration is greater in the potato cup as compared to the cavities made in them and solute concentration is greater in the cavities as compared to the potato as well as the trough containing water. So, osmosis occurs in the inward direction i.e from exterior into the cavities inside them. This process is called endosmosis.