Physics 2002 JAMB Past Questions - Question 21: Water is a poor thermometric liquid because it

Correct Answer

C

Explanation

Water is actually a very good thermometric liquid for many purposes, but it does have some limitations that make it less suitable for certain applications. Here are some reasons why water can be considered a poor thermometric liquid in some situations:

1. Limited Temperature Range: Water freezes at 0 degrees Celsius (32 degrees Fahrenheit) and boils at 100 degrees Celsius (212 degrees Fahrenheit at sea level). This limited temperature range makes it unsuitable for measuring extremely high or low temperatures without additional modifications, such as using antifreeze solutions for subzero temperatures.

2. Inconsistent Density Changes: Water's density changes with temperature in a non-linear fashion. It reaches its maximum density at approximately 4 degrees Celsius. Below 4 degrees Celsius, water becomes less dense as it freezes, which is contrary to the typical behavior of liquids. This can lead to inaccuracies in some thermometric measurements.

3. Expansion When Frozen: Water expands when it freezes, which can lead to problems in situations where the expansion needs to be avoided, such as in some industrial processes and equipment.

4. Limited Compatibility: In some industrial and scientific applications, water may not be compatible with the substances being measured or the equipment used for measurements. This can make it a poor choice in those situations.

5. Thermal Conductivity: Water has relatively high thermal conductivity, which can lead to rapid heat exchange with its surroundings, making it less suitable for situations where thermal isolation is important.

Despite these limitations, water is still a widely used thermometric liquid in many everyday applications, such as household thermometers, medical thermometers, and weather instruments. It is readily available, non-toxic, and inexpensive, making it a practical choice for a wide range of temperature measurement needs. However, for more specialized applications, other thermometric liquids or substances may be preferred due to their specific properties and characteristics.