11. In an experiment to determine the size of an oil molecule, clean water was placed in a large basin and then left over several minutes without any disturbance. Lycopodium powder was carefully spread
on the water surface. A drop of oil was then taken from a container using a fine wire. Its diameter was
measured using a millimeter scale with the aid of a hand lens and was found to be 0.35mm. The oil
drop was carefully transferred onto the water surface where it spread to form a circular patch of
diameter 14cm.
(a) Explain briefly why:
(0) It was important to use clean water for this experiment.
(1 marks)
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