Chapter U3.4, Problem 1TAI

Interpretation Introduction

Interpretation : Methods used to measure temperature are to be described.

Concept Introduction : Thermometer is an instrument used to measure temperature. It has a liquid which responds to increase or decrease in temperature. Temperature is degree of hotness or coldness.

Answer to Problem 1TAI

Matter responds to change in temperature by displaying change in volume. This property of matter is used to measure temperature.Two common ways to make a thermometer are:

1. A liquid thermometer can be made by filling a glass tube with a liquid. The volume of the liquid in a thermometer changes as the temperature changes.
2. Gas thermometers can be built by taking a container with a flexible volume filled with hot water containing trapped air in an inverted graduated cylinder.

Two commonly used scales are the Celsius scale and the Fahrenheit scale.

Explanation of Solution

Matter responds to change in temperature by displaying change in volume. Generally, increase in temperature causes matter to expand while cooling makes the matter contract. This property of matter is used to measure temperature. In solids, this change is very small while in gases the change is dramatic.

1. A simple thermometer can be made by filling a glass tube with a liquid. The volume of the liquid in a thermometer changes as the temperature changes. This is manifested by change in height of the liquid. This is known that volume and height are proportional to each other so increase in volume can be measured by increase in height.
2. Gas thermometers can be built by taking a container with a flexible volume filled with hot water containing trapped air in an inverted graduated cylinder. When the trapped air sample is heated, some air bubbles out of the cylinder and when trapped air is cooled some water rise into the cylinder.

To measure the temperature by thermometers, one needs to design a temperature scale for which minimum two points are needed; melting point and boiling point of water. Once these two points are marked, other points can be marked by dividing the length into regular intervals. Two commonly used scales are the Celsius scale and the Fahrenheit scale.

Conclusion

Most of the world and most scientists use Celsius scale while weather report in United States gives temperatures in Fahrenheit.