CBSE Class 6 Science Revision Notes Chapter 7: Temperature and its Measurement

Temperature is the reliable measure of how hot or cold a body is. In CBSE Class 6 Science, temperature is measured using clinical, laboratory and room thermometers.

Temperature tells us how hot or cold a body is. We may sometimes judge temperature by touching an object, but our sense of touch can give different results. A thermometer provides a more reliable measurement. This chapter introduces clinical, laboratory and room thermometers, along with the Celsius, Fahrenheit and Kelvin scales.

These CBSE Class 6 Science Revision Notes Chapter 7 follow the current 2026–27 chapter. Revise how body temperature is measured, how thermometer readings are taken correctly, and how range and smallest divisions are calculated. You will also learn about air temperature, boiling water, melting ice and the work of Anna Mani.

Key Takeaways

• Temperature: It measures the degree of hotness or coldness of a body.
• Body temperature: The average normal temperature of a healthy human body is 37.0 °C or 98.6 °F.
• SI unit: Kelvin, written as K, is the SI unit of temperature.
• Laboratory thermometer: Its usual range is from −10 °C to 110 °C.

Access Class 6 Science Chapter 7 Temperature and its Measurement Notes in 30 Minutes

Revise the chapter in three parts:

• • First 10 minutes: Hot and cold, temperature and thermometer types
  • Next 10 minutes: Clinical thermometers, body temperature and temperature scales
  • Final 10 minutes: Laboratory thermometers, correct readings and air temperature

• Need help revising thermometer readings and temperature scales?

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Hot or Cold in Class 6 Science Chapter 7 Notes

Some bodies feel hotter than others. For example, tap water in summer may feel warmer than water from an earthen pot.

However, touch does not always give a correct idea of temperature.

Why Can the Sense of Touch Be Misleading?

Consider three containers:

• Container A has warm water.
• Container B has water at room temperature.
• Container C has ice-cold water.

Keep one hand in warm water and the other in ice-cold water. After one or two minutes, place both hands in the room-temperature water.

The hand taken from warm water may feel that container B is cool. The hand taken from cold water may feel that the same water is warm.

Both hands touch the same water but give different feelings.

This activity shows that we cannot always rely on touch to decide whether a body is hot or cold.

Temperature and Thermometers Revision Notes

Temperature gives a reliable comparison of hotness or coldness.

A hotter body has a higher temperature than a colder body.

What Is Temperature?

Temperature is the reliable measure of how hot or cold a body is.

The difference in temperature between two bodies tells us which one is hotter or colder.

What Is a Thermometer?

A thermometer is a device used to measure temperature.

The chapter introduces three common thermometer types:

• Clinical thermometer
• Laboratory thermometer
• Room thermometer

Each thermometer has a different use and temperature range.

Clinical Thermometer in Class 6 Science Chapter 7 Notes

A clinical thermometer measures human body temperature.

Most clinical thermometers now display the reading digitally.

Digital Clinical Thermometer

A digital clinical thermometer works using heat sensors.

It usually contains:

• A sensing tip
• A digital display
• A reset or power button
• A battery

The thermometer measures temperature when its tip comes in contact with the body.

Why Are Digital Thermometers Commonly Used?

Earlier, mercury thermometers were used for measuring body temperature.

Mercury is toxic and difficult to dispose of safely if a thermometer breaks. Digital thermometers do not create this risk.

Their numerical display is also easier to read.

Non-contact Thermometers

Non-contact thermometers are also called infrared thermometers.

They can measure body temperature from a distance without touching the person.

These thermometers were commonly used during the COVID-19 pandemic because they reduced physical contact.

Correct Use of a Digital Clinical Thermometer

A digital clinical thermometer should be used carefully and hygienically.

Steps to Measure Body Temperature

1. Wash your hands.
2. Clean the thermometer tip with soap and water.
3. Keep the display part away from water.
4. Press the reset or power button.
5. Place the tip under the tongue.
6. Close the mouth gently.
7. Wait for the beep or flashing signal.
8. Remove the thermometer.
9. Read the number on the display.
10. Clean and dry the tip after use.

The exact method may vary slightly, so the instruction manual should also be checked.

Precautions for a Clinical Thermometer

• Clean the tip before and after use.
• Do not immerse the digital display in water.
• Do not hold the thermometer by its tip.
• Use the thermometer according to its instructions.
• Do not use it for boiling water or ice.

A clinical thermometer is designed for the limited range of human body temperature.

Normal Body Temperature Notes

The normal temperature of a healthy human body is taken as:

37.0 °C

This value is equal to:

98.6 °F

Is Everyone’s Normal Temperature Exactly 37.0 °C?

No. The value 37.0 °C is an average calculated from many healthy people.

A healthy person may have a slightly higher or lower temperature.

Body temperature may depend on:

• Age
• Time of day
• Physical activity
• Health condition

The temperature of the human body does not normally go below 35 °C or above 42 °C.

Body Temperature Through the Armpit

A digital thermometer may be placed in the armpit for small children or older people.

The temperature measured in the armpit may be about 0.5 °C to 1 °C lower than the actual body temperature.

This difference should be considered when interpreting the reading.

Why Is Pulse Rate Not a Reliable Fever Test?

Fever can affect pulse rate, and people once used pulse rate to judge fever.

However, physical activity, stress and other conditions can also change pulse rate.

Therefore, pulse rate alone cannot reliably confirm fever.

Temperature Scales in Chapter 7 Science Revision Notes

A temperature scale provides fixed markings and units for recording temperature.

The three common scales are Celsius, Fahrenheit and Kelvin.

Celsius Scale

The Celsius scale uses the unit degree Celsius.

Its symbol is:

°C

Body temperature and many daily temperature readings are commonly recorded in degree Celsius.

Example:

37.0 °C

Fahrenheit Scale

The Fahrenheit scale uses the unit degree Fahrenheit.

Its symbol is:

°F

The average normal body temperature is:

98.6 °F

This is equal to 37.0 °C.

Kelvin Scale

The Kelvin scale uses the unit kelvin.

Its symbol is:

K

Kelvin is the SI unit of temperature.

The degree sign is not used with kelvin.

Correct:

300 K

Incorrect:

300 °K

Celsius to Kelvin Conversion

Temperature in Kelvin = Temperature in Celsius + 273.15

For example:

27 °C + 273.15 = 300.15 K

This conversion is useful in scientific work.

Temperature Scale Comparison

Rules for Writing Temperature

Temperature values should be written using standard rules.

• Celsius, Fahrenheit and Kelvin begin with capital letters when naming the scales.
• The symbols °C, °F and K use capital letters.
• Kelvin does not use the degree sign.
• Leave a space between the number and unit.
• Do not add a full stop after the symbol unless it ends the sentence.

Correct examples:

37 °C

98.6 °F

300 K

Incorrect examples:

37°C

98.6°f

300 °K

Laboratory Thermometer Notes for Class 6

A laboratory thermometer measures temperatures for scientific activities.

It can measure temperatures beyond the range of a clinical thermometer.

Structure of a Laboratory Thermometer

A laboratory thermometer usually has:

• A long, narrow glass tube
• A bulb at one end
• A liquid inside the bulb
• A thin liquid column
• A marked Celsius scale

The liquid may be coloured alcohol or mercury.

The liquid column rises when the temperature increases and falls when it decreases.

The temperature is read at the top level of the liquid column.

Thermometer Range and Smallest Division

Before using a laboratory thermometer, check its range and smallest division.

Range of a Thermometer

The range tells us the lowest and highest temperatures a thermometer can measure.

A common school laboratory thermometer has the range:

−10 °C to 110 °C

This means it can measure temperatures from −10 °C up to 110 °C.

How to Find the Smallest Division

The smallest division is the value shown by one small mark.

Suppose:

• The difference between two large marks is 10 °C.
• There are 10 small divisions between them.

Smallest division = 10 °C ÷ 10

Smallest division = 1 °C

Therefore, each small mark represents 1 °C.

Different thermometers may have different ranges and smallest divisions. Always inspect the thermometer before use.

Correct Way to Measure Temperature

A laboratory thermometer must be placed and read correctly.

Correct Position of the Thermometer

Follow these points:

• Hold the thermometer vertically.
• Immerse the bulb fully in the liquid.
• Do not let the bulb touch the bottom.
• Do not let the bulb touch the sides.
• Keep the thermometer steady.
• Read while the bulb remains immersed.
• Keep the eye in line with the top of the liquid column.

Why Should the Bulb Not Touch the Beaker?

If the bulb touches the side or bottom, it may measure the temperature of the beaker instead of the liquid.

This can give an incorrect reading.

Why Must the Reading Be Taken While Immersed?

The liquid column begins to fall after the thermometer is removed from warm water.

Therefore, the correct reading must be noted while the bulb remains in the liquid.

Precautions for a Laboratory Thermometer

• Handle it carefully because the glass may break.
• Never hold it by the bulb.
• Keep it upright during measurement.
• Do not use it to measure body temperature.
• Do not touch hot experimental setups.
• Perform boiling-water activities under teacher supervision.

Clinical and Laboratory Thermometer Comparison

Clinical and laboratory thermometers are designed for different purposes.

A laboratory thermometer should not be used for body temperature because it is not designed for clinical use.

Temperature of Boiling Water and Melting Ice

A laboratory thermometer can measure the temperature of boiling water and melting ice.

Boiling Water

As water is heated, its temperature rises.

Once it starts boiling, the temperature remains nearly constant while boiling continues.

Students in different locations may record slightly different values. Conditions such as location, pressure and measurement method can affect readings.

For example, the NCERT activity in Shillong records values close to 98 °C.

Melting Ice

The temperature of ice also remains constant while it is melting.

The added energy helps change ice into water instead of raising the temperature immediately.

For Class 6 revision, remember the observed point:

Temperature remains constant while water boils and while ice melts.

Air Temperature in Temperature and its Measurement Notes

Air temperature tells us how hot or cold the surrounding air is.

It is an important part of weather observation.

Room Thermometer

A room thermometer gives an approximate value of room temperature.

It may be seen in:

• School laboratories
• Clinics
• Hospitals
• Rooms
• Weather stations

Maximum and Minimum Air Temperature

Weather reports often show:

• Maximum temperature of the day
• Minimum temperature of the day

These values usually change from day to day.

Temperature generally rises as summer approaches and falls during winter.

Air Temperature and Weather Forecasting

Weather stations monitor air temperature regularly.

This information is studied with other weather factors to prepare forecasts.

Recording daily maximum and minimum temperatures can help identify weather patterns.

Anna Mani and Temperature Measurement

Anna Mani was an Indian scientist known as the Weather Woman of India.

She invented and built many weather-measuring instruments.

Her work reduced India’s dependence on imported scientific instruments.

She also studied:

• Wind energy
• Solar energy
• Weather measurement

Her work supported the development of weather science and renewable energy in India.

Class 6 Science Chapter 7 Summary Notes

Important Terms from Temperature and its Measurement

Temperature: A reliable measure of the hotness or coldness of a body.

Thermometer: A device used to measure temperature.

Clinical thermometer: A thermometer used to measure human body temperature.

Digital thermometer: A thermometer that displays temperature as a number.

Non-contact thermometer: A thermometer that measures temperature without touching the body.

Laboratory thermometer: A thermometer used for scientific measurements.

Celsius scale: A temperature scale with the unit degree Celsius.

Fahrenheit scale: A temperature scale with the unit degree Fahrenheit.

Kelvin scale: A scientific temperature scale whose unit is kelvin.

Range: The lowest and highest values a thermometer can measure.

Smallest division: The value represented by one small scale mark.

Air temperature: The temperature of the surrounding air.

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