Study carefully the experimental set-ups labelled A, B and C.
(a) What is the aim of the experiment for which the apparatus has been set up?
(b) List the experimental set-ups in the order in which water has risen through the soil samples, starting with the highest
(c) List six items of apparatus used in the experimental set-up.
(d) Describe briefly the procedure used in setting up the experiment.
(e) Why is there a difference in the water levels of the soil samples in the set ups labelled B and C?
Explanation
(a) The aim of the experimental setup is:
(i) To compare/determine the amount/level of the capillarity attraction of different types of soils
(ii) To compare the capillary movement of water in different soil types.
(b) The rise in water is in the following order;
- Specimen C - Highest - Sand
- Specimen A - Higher - Loam
- Specimen B - Lowest - clay. (Note: These levels are what may be observed within the time limit given for the experiment. If longer the levels would change.)
(c) Apparatus used in the experimental setup:
(i) A large beaker/basin/dish/trough
(ii) Three capillary tubes/glass tubes.
(iii) Soil samples A, B, and C.
(iv) Water
(v) Cotton wool
(vi) Clamps
(vi) Retort stands.
(d) Description of the procedure used in setting up the experiment:
(i) Take three glass tubes and plug each with cotton wool at one end.
(ii) Dry the soil samples and break up the lumps into smaller particles/or grind.
(iii) Fill each tube with equal quantíties of dry samples of clayey, loamy and sandy soils.
(iv) Fix the three tubes in an upright position with clamps.
(v) Get the three glass tubes immersed in a trough of water.
(vi) Allow to stand for the required time.
(vii) Watch the upward movement of water into the soil samples and record your observation.
(e) Why there is a difference in the water levels in soil samples B and C:
(i) In sample C. sand the larger particles and pore spaces allow water to rise much faster than in clay (sample B) but stop soon because of low capillary attraction.
(ii) In sample B, clay, the very fine particles and pore spaces do not allow water to penetrate and rise fast, but as the clay particles absorb water and swell, there is greater capillarity attraction which enables the level to rise up more than sand later.