Viscosity
The students were asked to vote on which marble would fall to the bottom in which fluid
first. We treated the entire situation as a race. We allowed three students to drop
each marble. Once the race was over we asked the students to tell us why the marble
dropped fastest in the water and slowest in the glycerol. We explained to the students
that it was due to the different viscosities of the fluid.
For the younger students we defined viscosity and density without
using the words viscosity and density. For the definitions see the theory page.
Question: Three black marbles are dropped into three different fluids at the same time. What
will happen and why?

Answer: The marble will drop the fastest in the water and slowest in the glycerol. The
reason is due to the different viscosities of the fluids.
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Demo
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