4. Complete Activity 5.4 (Page 52).
• Put dried raisins or apricots in plain water and leave them for some time. Then place them into a concentrated solution of sugar or salt.
Answer:
Aim: To observe what happens when dried raisins are placed in plain water and then placed in a concentrated solution of sugar or salt and conclude based on that.
Materials Required: Dried raisins, water, salt.
Procedure:
(i) Place the dried raisins in pure water and leave them for some time.
(ii) After that, place them into a concentrated solution of salt.
Observations:
- When placed in pure water, the raisins gain water and swell.
- When placed in the concentrated salt solution it loses water, and shrinks
Conclusions:
- When placed in pure water, the concentration of solute inside the raisins is more than outside. Hence, water enters the raisins by the process of osmosis and they swell.
- When placed in concentrated salt solution, the concentration of solute outside the raisins is more than the inside. Hence, water passes out of the raisins by the process of osmosis and they shrink.
- Thus, osmosis is the net diffusion of water across a selectively permeable membrane toward a higher solute concentration.
“Put dried raisins or apricots in plain water and leave them for some time. Then place them into a concentrated solution of sugar or salt.” – Solved.
Related Links:
Solution to Activity 5.1
Solution to Activity 5.2
Solution to Activity 5.3
Solution to Activity 5.4
Solution to Activity 5.5
Solution to Activity 5.6
Solution to Activity 5.7
Solution to Chapter 5 The Fundamental Unit of Life
