How does an increase in temperature affect liquids?
Increasing the temperature of a liquid tends to:
A. Increase viscosity and decrease density
B. Increase viscosity and increase density
C. Decrease viscosity and decrease density
D. Decrease viscosity and increase density
Commentary
In general, liquids tend to get "thinner" when their temperature increases. For example, honey and oil tend to flow better at higher temperatures. Therefore, increasing temperature decreases viscosity. Answer A and Answer B are not correct.
In general, the liquids tend to expand when their temperature increases. For example, the same mass of boiling water occupies more volume at 100 degrees Celsius than at 20 degrees Celsius. Therefore, increasing temperature decreases density. Answer C is correct.
Additional complicating factors
The viscosity of liquids is affected by temperature. However some liquids are Non-Newtonian and their viscosity can be much more affected by how they are treated. For example, trying to pump certain slurries using more energy can cause the apparent viscosity to increase. This in turn causes the slurry to exhibit more resistance and can actually reduce the flowrate—even though more energy is used.
| Related Content: – “Part II: The Expert Witness” By David W. Spitzer |
While liquid density generally decreases with increasing temperature, this is not always the case. For example, the density of water between about 0 and 4 degrees Celsius will actually increase with increasing temperature.
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David W. Spitzer
David W Spitzer’s new book Global Warming (aka Climate Change): An Understandable Data-Driven Explanation and Pathway to Mitigation (Amazon.com) adds to his over 500 technical articles and 10 books on flow measurement, instrumentation, process control and variable speed drives. David offers consulting services and keynote speeches, writes/edits white papers, presents seminars, and provides expert witness services at Spitzer and Boyes LLC (spitzerandboyes.com or +1.845.623.1830).
