The primary sector involves activities that:

produce goods directly from nature

Which of these belongs to the secondary sector?

Manufacturing cloth from cotton in a factory

What device measures temperature, and what are its two common types?

A thermometer measures temperature; the two common types are the clinical thermometer for body temperature and the laboratory thermometer for other purposes.

What is the normal temperature of a healthy human body?

The normal temperature of a healthy human body is taken to be 37.0 °C, which is equal to 98.6 °F, though it varies slightly between people.

What are the three temperature scales, and which gives the SI unit?

The Celsius scale (°C), the Fahrenheit scale (°F), and the Kelvin scale (K); the kelvin from the Kelvin scale is the SI unit of temperature.

How do you convert a Celsius temperature to the Kelvin scale?

Using the relation \( T_{K} = T_{C} + 273.15 \), that is, the Kelvin temperature equals the Celsius temperature plus 273.15.

What is the usual range of a laboratory thermometer?

A laboratory thermometer usually has a range from –10 °C to 110 °C.

Why can a clinical thermometer not be used to measure the temperature of boiling water or ice?

Because the temperatures of boiling water and ice lie outside the limited range of a clinical thermometer, which is meant only for body temperature.

What is the correct way to read a laboratory thermometer?

The bulb should be immersed without touching the bottom or sides, the thermometer held vertically, and the reading taken while immersed with the eye level with the top of the liquid column.

Why are mercury clinical thermometers being replaced by digital ones?

Because mercury is extremely toxic and hard to dispose of if the thermometer breaks, while digital thermometers pose no such risk and are easier to read.

Temperature and its Measurement

Q: Why is our sense of touch not a reliable way to judge hotness or coldness?

Because after dipping hands in warm and cold water, the same water in a third container feels warm to one hand and cool to the other, so touch gives different results.

Q: What is temperature?

Temperature is a reliable measure of the hotness or coldness of a body; a hotter body has a higher temperature than a colder one.

Class 6 Science · Curiosity · Chapter 7

158 members in the CBSE community

View all

CBSE Class 6 · Science

12 chapters: food tests to the night sky

Marks booster + cheatsheet: key concepts in 2 lines each, common traps
Plant and animal groups, Ch 2
Temperature and its measurement, Ch 7
Common traps, corrected
Methods of separation, Ch 9
10 must-know facts with a self-check

₹19See the full kit

CBSE Class 6 · All available subjectsTrending

All 5 Class 6 kits: each book, by chapter

Science: 12 chapters, with traps corrected
Maths: 10 chapters, primes to integers
Hindi: 13 मल्हार lessons, 16 grammar points
English: all 16 Poorvi texts, unit by unit
Social Science: 14 chapters, maps to sectors
5 kits, one per subject

₹69See the full kit

View all 6 amazing Marks Booster kits →

Summary

This chapter explains how we measure how hot or cold a body is. It opens with the insight that our sense of touch is unreliable: after dipping one hand in warm water and the other in cold, the same water in a third container feels warm to one hand and cool to the other. Therefore we need a reliable measure of hotness or coldness, called temperature, and a device that measures it, called a thermometer. The chapter describes the clinical thermometer used for body temperature, noting that modern digital thermometers have replaced toxic mercury ones, and even infrared (non-contact) thermometers that measure temperature from a distance, as used during the COVID-19 pandemic. The normal temperature of a healthy human body is taken to be 37.0 °C (98.6 °F), though it varies slightly with age, time of day, and activity, and the human body normally stays between 35 °C and 42 °C. Temperature is measured on three scales: the Celsius scale (degree Celsius, °C), the Fahrenheit scale (degree Fahrenheit, °F), and the Kelvin scale, whose unit, the kelvin (K), is the SI unit of temperature; the conversion is \( T_{K} = T_{C} + 273.15 \). The chapter then introduces the laboratory thermometer, which has a liquid (alcohol or mercury) in a sealed glass tube with a Celsius scale, and explains how to read its range (typically –10 °C to 110 °C) and the value of its smallest division. It teaches the correct way to use it: the bulb must be immersed without touching the bottom or sides, the thermometer held vertically, the reading taken while still immersed and with the eye level with the liquid. A clinical thermometer cannot measure boiling water or ice because these lie outside its range. Air temperature, measured by room and weather thermometers, varies daily and is used for weather forecasts.

Why touch is unreliableTemperature and thermometersClinical thermometers and scalesLaboratory thermometers and correct useAir temperature and weather

Key terms

Temperature

A reliable measure of the hotness or coldness of a body; a hotter body has a higher temperature than a colder one.

Thermometer

A device used to measure temperature; clinical thermometers measure body temperature and laboratory thermometers are used for many other purposes.

Clinical thermometer

A thermometer used to measure human body temperature, usually digital today, replacing the older toxic mercury type.

Laboratory thermometer

A thermometer with a liquid column in a sealed glass tube and a Celsius scale, used to measure temperatures over a wide range, typically –10 °C to 110 °C.

Temperature scales

The Celsius scale (°C), the Fahrenheit scale (°F), and the Kelvin scale (K); the kelvin is the SI unit of temperature.

Normal body temperature

The average body temperature of healthy people, taken to be 37.0 °C (98.6 °F), with the human body normally between 35 °C and 42 °C.

Extra questions & answers

Let us enhance our learning

Try one from this chapter

Why is our sense of touch not a reliable way to judge hotness or coldness?

Flashcards & interactive practice