Math CentralQuandaries & Queries


Question from Nursing, a student:

In determining the density of a liquid, a student left air bubbles trapped in the volumetric pipet. Did this give a density less than expected or greater than expected? Why?


When you measure the mass of the liquid you measure it without the trapped bubbles and hence the mass measurement should be correct. With the bubbles in the pipet however the volume measurement is incorrect, it is too large. Thus in the calculation density = mass/volume the denominator is increased by the volume of the bubbles and when you increase the denominator of a fraction the value of the fraction decreases. Thus the density you obtain from this calculation is too small.


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