When an alcohol thermometer is placed in 20-degree centigrade water the thermometer will record a temperature greater than 20 degrees centigrade. According to the equation
T = v / v β
The temperature change is inversely related to the coefficient of expansion. The value of beta for alcohol is 1.12 x 10-4 C -1.
So, the temperature recorded by the alcohol thermometer would be greater than 20.
Further explanation about the temperature recording:
Temperature:
It is a physical quantity that measures the hotness or coldness of any substance. The device used to degree temperature is a thermometer. Three commonplace scales are there to degree the temperature of a substance.
Volume expansion occurs when a substance is expanded in three-dimensional space. The expression for volume expansion is as follows:
…… (1)
Here,
is the change in volume.
is the initial volume.
is the coefficient of volume expansion.
is the temperature change.
Rearrange equation (1) for .
…… (2)
The temperature change is inversely related to the coefficient of volume expansion. The value of 
for mercury is 1.82 x 10-4 C -1 and that for alcohol is 1.82 x 10-4 C -1. So the temperature recorded by the alcohol thermometer will be greater than .
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