Question

When small particles settle through water faster than large particles, the small particles are probably

a.lighter
b.flatter
c.better sorted
d.more dense?

Answer 1

d. if an object is less dense it will float / sink slower than an object with a higher density :)

Answer 2

Answer: option d. more dense.

Justification:

1) The speed of the particle falling to the bottom of the vessel is given by the balance of two forces: the weight of the particle (which is downward) and the buoyance (which is upward).

2) The buoyance depends on the density. The shape also may influence in the speed of settling, as a drag force is developed on flat surfaces. Since the statement says that the partcles are settling faster, they can not be flatter.

3) In general, you know that the denser an object the faster it will sink (settle) becasue the buyounace force is smaller. So, the right option is the d. more dense. The particles cannot be lighter because this is pposite to denser.

Sorting is not a driving force for the settling.