What should the student in the video do next?
Answer: C. Centrifuge the sample again, and allow the centrifuge
to stop gradually.
The student will not be able to decant the supernatant without
removing a portion of the solid, since the solid became dispersed
into the solution when the centrifuge was stopped suddenly, so
A and B are inappropriate answers. In addition, choice D is not
a good solution, because the solid in the sample can be re-centrifuged
quickly. Repeating the experiment would waste laboratory time.