NCERT Solutions for Class 6 Science (Curiosity) Chapter 7: Temperature and its Measurement (NCERT 2026–27)

These Class 6 Science Curiosity Chapter 7 solutions cover Temperature and its Measurement from the new NCF textbook (2026–27). The chapter explains why our sense of touch is unreliable for judging hotness, what temperature really means, the three temperature scales (Celsius, Fahrenheit and Kelvin), and how to read clinical, laboratory and room thermometers correctly. All 14 “Let us enhance our learning” questions are answered below, with checked thermometer readings, coloured scales and worked least-count calculations.

Class: 6 Subject: Science Book: Curiosity Chapter: 7 Exercise: Let us enhance our learning Session: 2026–27
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Class 6 Science Curiosity Chapter 7 Solutions – Overview

Chapter 7 of Curiosity, Temperature and its Measurement, begins with a simple experience — we can feel that some bodies are hotter than others, but our sense of touch is not reliable for deciding exactly how hot or cold a body is. A trustworthy measure of hotness or coldness is its temperature, and the device that measures it is a thermometer. The chapter describes the clinical thermometer (used for body temperature, now mostly digital because mercury is toxic), the laboratory thermometer (range usually −10 °C to 110 °C) and the room thermometer. It introduces the three scales — Celsius (°C), Fahrenheit (°F) and Kelvin (K, the SI unit) — with the relation Kelvin = Celsius + 273.15, and stresses the correct way to read a thermometer with the eye level with the liquid column.

Key Concepts & Definitions

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 thermometer: used to measure human body temperature; modern ones are digital and run on batteries.

Laboratory thermometer: a sealed glass tube with a bulb of liquid (alcohol or mercury) and a Celsius scale; its range is usually −10 °C to 110 °C.

Temperature scales: Celsius (unit degree Celsius, °C), Fahrenheit (unit degree Fahrenheit, °F) and Kelvin (unit kelvin, K). The SI unit of temperature is the kelvin.

Key values: A commonly used normal-body reference is 37.0 °C = 98.6 °F; healthy readings vary. Kelvin = Celsius + 273.15. Absolute zero ≈ −273.15 °C (0 K).

Smallest value (least count): the smallest temperature difference a thermometer can read = (difference between two big marks) ÷ (number of divisions between them).

“Let us enhance our learning” — NCERT Solutions

Questions 1–14 follow NCERT Curiosity Chapter 7, pages 137–140. Figure-based answers have been checked against the textbook; the diagrams below are original teaching redrawings.

1. The normal temperature of a healthy human being is close to ________. (i) 98.6 °C    (ii) 37.0 °C    (iii) 32.0 °C    (iv) 27.0 °C

ANSWER (ii) 37.0 °C. The normal temperature of a healthy human body is taken to be 37.0 °C on the Celsius scale (the same as 98.6 °F). Option (i) is wrong because 98.6 is the Fahrenheit value, not the Celsius value.

2. 37 °C is the same temperature as ________. (i) 97.4 °F    (ii) 97.6 °F    (iii) 98.4 °F    (iv) 98.6 °F

ANSWER (iv) 98.6 °F. A temperature of 37.0 °C on the Celsius scale is equivalent to 98.6 °F on the Fahrenheit scale — this is the normal body temperature.

3. Fill in the blanks: (i) The hotness or coldness of a system is determined by its ________. (ii) The temperature of ice-cold water cannot be measured by a ________ thermometer. (iii) The unit of temperature is degree ________.

ANSWER (i) temperature — temperature is the reliable measure of how hot or cold a system is. (ii) clinical — a clinical thermometer reads only the narrow human-body range (about 35 °C to 42 °C), so the temperature of ice-cold water (well below this range) cannot be measured with it. (iii) Celsius (or Fahrenheit) — the unit of temperature is the degree Celsius (°C) on the Celsius scale, or the degree Fahrenheit (°F) on the Fahrenheit scale.

4. The range of a laboratory thermometer is usually ________. (i) 10 °C to 100 °C    (ii) −10 °C to 110 °C    (iii) 32 °C to 45 °C    (iv) 35 °C to 42 °C

ANSWER (ii) −10 °C to 110 °C. A laboratory thermometer typically reads from −10 °C to 110 °C, so it can measure temperatures below the freezing point of water and above its boiling point. (Option (iv) 35 °C to 42 °C is the range of a clinical thermometer.)

5. Four students used a laboratory thermometer to measure the temperature of water as shown in Fig. 7.6. Who do you think followed the correct way for measuring temperature? (i) Student 1    (ii) Student 2    (iii) Student 3    (iv) Student 4

ANSWER(ii) Student 2. The thermometer is upright, with its bulb fully immersed and away from the beaker’s sides and bottom.Student 1 tilts it, Student 3 lets it touch the bottom, and Student 4 places it against the side. In addition to correct placement, wait for the reading to settle and read at eye level while the bulb remains immersed.
Four thermometer placements: tilted, correctly immersed upright, touching base, and touching side; Student 2 is correct.
Q5: placement must let the bulb measure the water. Tap to view at full size.

6. Colour to show the red column on the drawings of thermometers (Fig. 7.7) as per the temperatures written below: 14 °C, 17 °C, 7.5 °C.

ANSWER14 °C: the first scale has 2 °C per small interval. Colour to the second small mark above 10 °C. It is not the midpoint between 10 and 20; that would be 15 °C.17 °C: the second scale has 1 °C per interval. Colour to the seventh small mark above 10 °C.7.5 °C: the third scale has 0.5 °C per interval. Colour to the mark halfway between 7 and 8 °C. Check the different scales rather than assuming their divisions are identical.
Thermometers with red columns at 14, 17 and 7.5 degrees Celsius, using 2, 1 and 0.5 degree intervals respectively.
Q6: each scale has a different smallest division. Tap to view at full size.

7. Observe the part of thermometer shown in Fig. 7.8 and answer the following questions: (i) What type of thermometer is it? (ii) What is the reading of the thermometer? (iii) What is the smallest value that this thermometer can measure?

ANSWER(i) A laboratory thermometer.(ii) 26 °C. The liquid column reaches the first small mark after 25 °C in Fig. 7.8.(iii) 1 °C. The gap from 20 °C to 30 °C contains 10 equal intervals, so each interval is (30 − 20) ÷ 10 = 1 °C.
Enlarged scales: Q7 reads 26 degrees Celsius; Q11 reads 27.5; Q13 has 20 half-degree intervals between 10 and 20.
Readings for Q7 and Q11, and a model half-degree scale for Q13. Tap to view at full size.

8. A laboratory thermometer is not used to measure our body temperature. Give a reason.

ANSWERThe glass laboratory thermometer in this chapter is not designed for safe clinical use. Its liquid column changes as soon as it is removed from the body, so it does not retain the body-temperature reading.Use a suitable clinical thermometer and follow its instructions. A digital clinical thermometer retains a displayed reading electronically; this should not be confused with the kink in an older mercury clinical thermometer.

9. Vaishnavi has not gone to school as she is ill. Her mother has kept a record of her body temperature for three days as shown in Table 7.4.

Table 7.4: Body temperature record of Vaishnavi
DAY7 am10 am1 pm4 pm7 pm10 pm
One38.0 °C37.8 °C38.0 °C38.0 °C40.0 °C39.0 °C
Two38.6 °C38.8 °C39.0 °C39.0 °C39.0 °C38.0 °C
Three37.6 °C37.4 °C37.2 °C37.0 °C36.8 °C36.6 °C

(i) What was Vaishnavi’s highest recorded temperature? (ii) On which day and at what time was Vaishnavi’s highest temperature recorded? (iii) On which day did Vaishnavi’s temperature return to normal?

ANSWER(i) The highest recorded temperature is 40.0 °C.(ii) It was recorded on Day One at 7 pm.(iii) Day Three; the record reaches the textbook reference value of 37.0 °C at 4 pm. The readings fall during that day. A temperature table alone does not establish that a person has fully recovered.

10. If you have to measure the temperature 22.5 °C, which of the following three thermometers will you use (Fig. 7.9)? Explain.

ANSWERChoose thermometer (b) in Fig. 7.9. It covers 22.5 °C and has 0.5 °C per small interval, so 22.5 °C falls on a marked division.Thermometer (a) has 1 °C intervals and (c) has 2 °C intervals. Their marked scales do not directly resolve 22.5 °C. The range alone is not enough; the spacing of the divisions matters too.

11. The temperature shown by the thermometer in Fig. 7.10 is (i) 28.0 °C    (ii) 27.5 °C    (iii) 26.5 °C    (iv) 25.3 °C

ANSWER(ii) 27.5 °C. The scale has 0.5 °C intervals. The red column ends halfway between 27 °C and 28 °C, or five small intervals after 25 °C: 25 + (5 × 0.5) = 27.5 °C.The answer comes from the column position and scale, not from which option seems more likely.

12. A laboratory thermometer has 50 divisions between 0 °C and 100 °C. What does each division of this thermometer measure?

ANSWER Smallest value of one division = (total temperature difference) ÷ (number of divisions). = (100 °C − 0 °C) ÷ 50 = 100 ÷ 50 = 2 °C. So each division of this thermometer measures 2 °C.

13. Draw the scale of a thermometer in which the smallest division reads 0.5 °C. You may draw only the portion between 10 °C and 20 °C.

ANSWER Between 10 °C and 20 °C the total difference is 10 °C. If each small division is to read 0.5 °C, the number of divisions needed = 10 ÷ 0.5 = 20 divisions. So draw a vertical line, mark 10 °C at the bottom and 20 °C at the top, then divide the gap into 20 equal small parts (each = 0.5 °C). Make the lines at 10, 11, 12 … 20 °C slightly longer (bigger marks) with one small line halfway between each pair of whole degrees. This is the required 0.5 °C scale.

14. Komal tells you that she has a fever of 101 degrees. Does she mean it on the Celsius scale or Fahrenheit scale?

ANSWERShe means 101 °F, on the Fahrenheit scale. This is approximately (101 − 32) × 5/9 = 38.3 °C, which is consistent with a fever.101 °C would be far outside a living person’s body-temperature range. Always include the scale when reporting a temperature.

Extra Practice Questions

These questions and MCQs are ClearStudy practice, separate from the NCERT exercise.

Short Answer Type Questions

Q1. Why can we not always rely on our sense of touch to decide how hot or cold a body is?

ANSWEROur skin compares the body it touches with its own present state, not with a fixed standard. After holding warm water and then ice-cold water, the same tap water can feel cool to one hand and warm to the other at the same time. So touch gives different, misleading impressions and is unreliable; we use a thermometer for a correct measure.

Q2. State two precautions to be taken while using a laboratory thermometer.

ANSWER(a) Handle it with care — if it hits a hard object it can break. (b) Do not hold it by the bulb; hold it from the upper end. (Also: keep it vertical and read while the bulb is still immersed, with the eye level with the liquid column.)

Q3. Why are mercury clinical thermometers being replaced by digital ones?

ANSWERMercury is an extremely toxic substance and is difficult to dispose of if the thermometer breaks accidentally. Digital thermometers pose no such risk, are safer, and their displayed numbers are easier to read, so they are replacing mercury thermometers.

Q4. Convert 27 °C into the Kelvin scale.

ANSWERTemperature in Kelvin = Temperature in Celsius + 273.15 = 27 + 273.15 = 300.15 K.

Q5. What is a non-contact (infrared) thermometer, and why was it useful during the COVID-19 pandemic?

ANSWERAn infrared thermometer measures a person’s temperature without touching the body. During the COVID-19 pandemic it allowed temperatures to be checked from a distance, which reduced the risk of spreading the disease from person to person.

Long Answer Type Questions

Q1. Describe the correct way of measuring the temperature of warm water using a laboratory thermometer.

ANSWERDip the thermometer into the warm water so that the bulb is fully immersed, but make sure the bulb does not touch the bottom or the sides of the beaker, as these may be at a different temperature. Hold the thermometer vertically — it should not be tilted. Watch the liquid column rise and wait until it stops rising, but do not wait too long or the water will start to cool. Read the temperature while the thermometer is still immersed in the water, because the column begins to fall as soon as it is taken out. While reading, keep your eye directly in line with the top level of the liquid column to avoid an error. The scale mark that the top of the column coincides with is the temperature of the water.

Q2. Explain the three temperature scales and the SI unit of temperature, with the key fixed values.

ANSWERThere are three commonly used temperature scales. On the Celsius scale the unit is the degree Celsius (°C), and clinical thermometers usually use it; normal body temperature is 37.0 °C. On the Fahrenheit scale the unit is the degree Fahrenheit (°F); 37.0 °C equals 98.6 °F, but this scale is no longer used in most scientific work. On the Kelvin scale the unit is the kelvin (K), and this is the SI unit of temperature. We convert Celsius to Kelvin using: Temperature in Kelvin = Temperature in Celsius + 273.15. The lowest possible temperature, called absolute zero, is about −273.15 °C, which is 0 K. Note that the degree sign is not written with K.

Q3. Why does the normal body temperature of healthy people vary, and how is body temperature affected by various factors?

ANSWER37.0 °C is a commonly used reference value. A healthy person’s reading can differ with age, time of day, activity, thermometer and measurement site.Armpit readings often differ from mouth readings; follow the device instructions rather than applying a fixed correction to everyone. The interval 35–42 °C mentioned in the chapter is not a healthy normal range.

MCQs & Assertion–Reason

1. A reliable measure of how hot or cold a body is, is called its:

(a) weight    (b) temperature    (c) length    (d) mass

2. The SI unit of temperature is:

(a) degree Celsius    (b) degree Fahrenheit    (c) kelvin    (d) joule

3. The normal temperature of a healthy human body is:

(a) 37.0 °C    (b) 27.0 °C    (c) 47.0 °C    (d) 100 °C

4. The usual range of a laboratory thermometer is:

(a) 35 °C to 42 °C    (b) −10 °C to 110 °C    (c) 0 °C to 50 °C    (d) 10 °C to 100 °C

5. The liquid generally used in a laboratory thermometer is:

(a) water    (b) oil    (c) alcohol or mercury    (d) honey

6. 37 °C on the Celsius scale is the same as:

(a) 97.4 °F    (b) 98.4 °F    (c) 98.6 °F    (d) 100 °F

7. A thermometer that measures temperature without touching the body is a:

(a) clinical mercury thermometer    (b) infrared (non-contact) thermometer    (c) laboratory thermometer    (d) room thermometer

8. A laboratory thermometer has 100 divisions between 0 °C and 100 °C. Each division measures:

(a) 0.5 °C    (b) 1 °C    (c) 2 °C    (d) 10 °C

9. The temperature in Kelvin equals the temperature in Celsius:

(a) minus 273.15    (b) plus 273.15    (c) times 9/5    (d) plus 32

10. While reading a laboratory thermometer, your eye should be:

(a) above the liquid column    (b) below the liquid column    (c) level with the top of the liquid column    (d) anywhere you like

Answer key: 1-(b), 2-(c), 3-(a), 4-(b), 5-(c), 6-(c), 7-(b), 8-(b), 9-(b), 10-(c).

For each Assertion–Reason question, choose: (A) Both true and the Reason correctly explains the Assertion; (B) Both true but the Reason is not the correct explanation; (C) Assertion true, Reason false; (D) Assertion false, Reason true.

A-R 1. Assertion: Our sense of touch cannot always tell correctly how hot or cold a body is.

Reason: The same water can feel warm to one hand and cool to the other depending on what each hand touched before.

A-R 2. Assertion: A clinical thermometer cannot be used to measure the temperature of boiling water.

Reason: The temperature of boiling water lies outside the range of a clinical thermometer.

A-R 3. Assertion: The bulb of a laboratory thermometer should touch the bottom of the beaker while measuring.

Reason: The bulb should measure the water itself without touching the beaker’s bottom or sides.

A-R 4. Assertion: Mercury thermometers are being replaced by digital thermometers.

Reason: Mercury is highly toxic and hard to dispose of if the thermometer breaks.

A-R 5. Assertion: The kelvin is the SI unit of temperature.

Reason: The Kelvin scale is named in honour of the scientist who developed it.

Answer key: 1-(A), 2-(A), 3-(D), 4-(A), 5-(B).

Quick Revision Summary

  • Temperature is a reliable measure of how hot or cold a body is; our sense of touch is not reliable.
  • A thermometer measures temperature: clinical (body), laboratory (general use) and room thermometers.
  • Three scales: Celsius (°C), Fahrenheit (°F) and Kelvin (K); the SI unit is the kelvin.
  • Normal body temperature = 37.0 °C = 98.6 °F; healthy readings vary; 35–42 °C is not a healthy normal range.
  • Kelvin = Celsius + 273.15; absolute zero ≈ −273.15 °C = 0 K.
  • Laboratory thermometer range is usually −10 °C to 110 °C; smallest value = (gap between big marks) ÷ (number of divisions).
  • Read with the thermometer vertical, bulb immersed (not touching the beaker), eye level with the column.

Common Mistakes to Avoid

Watch out for these

  • Writing 98.6 °C for normal body temperature — 98.6 is the Fahrenheit value; in Celsius it is 37.0 °C.
  • Using a clinical thermometer for ice or boiling water — those temperatures are outside its range.
  • Letting the bulb touch the bottom or sides of the beaker, or reading after taking the thermometer out of the water.
  • Writing a degree sign with kelvin (°K) — the correct symbol is just K, with no degree sign.
  • Forgetting the 0.5 °C step — the smallest value depends on the divisions, so read it from the scale, not by guessing.
  • Reading the column with the eye too high or too low instead of level with the liquid surface.

How to write a clear answer

Memorise the key numbers exactly: 37.0 °C = 98.6 °F, laboratory range −10 °C to 110 °C, and Kelvin = Celsius + 273.15. For “smallest value” questions, always show the division: (difference between big marks) ÷ (number of small divisions). In reasoning questions (like the 101-degree one), back your answer with a fact — the human body never reaches 101 °C because it lies above boiling water. Always state units and never put a degree sign before K.

Frequently Asked Questions

What is Class 6 Science Curiosity Chapter 7 about?

Chapter 7, Temperature and its Measurement, explains that temperature is a reliable measure of hotness or coldness (unlike our sense of touch), introduces clinical, laboratory and room thermometers, and covers the Celsius, Fahrenheit and Kelvin scales, with normal body temperature being 37.0 °C (98.6 °F).

What is the normal temperature of a healthy human body?

The normal temperature of a healthy human adult is taken to be 37.0 °C on the Celsius scale, which is the same as 98.6 °F on the Fahrenheit scale. It is an average value, so a healthy person may be slightly higher or lower.

What is the SI unit of temperature?

The SI unit of temperature is the kelvin (K). We convert a Celsius temperature to kelvin using: Temperature in Kelvin = Temperature in Celsius + 273.15. Note that no degree sign is written with K.

Are these Class 6 Science Curiosity Chapter 7 solutions free?

Yes. All solutions are free and follow the official NCERT Curiosity (Grade 6) textbook for the 2026–27 session.

Sources: NCERT Curiosity Chapter 7 (official PDF); MedlinePlus body temperature norms. Use these as school explanations, not a diagnosis from a temperature reading alone.

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