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. Every question of the “Let us enhance our learning” exercise is reproduced word-for-word and solved step by step below.

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: Normal body temperature of a healthy adult = 37.0 °C = 98.6 °F. 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

All questions below are reproduced verbatim from the NCERT Curiosity (Grade 6) textbook, Chapter 7. Answers are original and exam-ready.

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 Student 2 — the student who held the thermometer vertically (not tilted) with the bulb fully immersed in the water but not touching the bottom or the sides of the beaker, and read it with the eye in line with the top of the liquid column. The correct way is: keep the thermometer upright, immerse only the bulb without it touching the beaker walls or base, read while it is still in the water, and keep the eye level with the liquid column. (Choose the figure that shows this; in the standard NCERT figure it is Student 2.)

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.

ANSWER On each thermometer, fill (colour red) the liquid column up to the mark that matches the given reading: 14 °C — colour up to the line midway between the 10 °C and 20 °C marks, four small divisions above 10 °C (taking each small division as 1 °C). 17 °C — colour up to seven small divisions above the 10 °C mark (a little below 20 °C). 7.5 °C — colour up to a point halfway between the 7 °C and 8 °C marks, just below the 10 °C line. (Activity-based; colour the column on the textbook figures as described.)

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) It is a laboratory thermometer — a glass tube with a liquid column and a Celsius scale marked along it. (ii) The reading is the mark of the Celsius scale with which the top of the liquid column coincides. Read off the value shown by the top of the red/silver column in the figure and write it with the unit, e.g. the indicated whole-degree or half-degree mark in °C. (iii) The smallest value = (temperature difference between two big marks) ÷ (number of small divisions between them). For example, if there are 10 small divisions between marks 10 °C apart, the smallest value is 10 ÷ 10 = 1 °C; if there are 20 divisions, it is 10 ÷ 20 = 0.5 °C. (Count the divisions shown in Fig. 7.8 to state the exact value.)

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

ANSWER A laboratory thermometer is not used for body temperature mainly because its reading falls quickly the moment it is taken out of contact — the liquid column drops as soon as the bulb leaves the body, so we cannot read the body temperature outside. In addition, it is long and has no ‘kink’ to hold the reading, and a clinical thermometer is specially designed (and digital nowadays) to safely and accurately measure the narrow human-body range. So a clinical thermometer is used instead.

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) Her highest recorded temperature was 40.0 °C. (ii) It was recorded on Day One at 7 pm. (iii) Her temperature returned to normal on Day Three — the readings (37.6 °C down to 36.6 °C) are around the normal value of 37.0 °C, showing she had 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.

ANSWER I would choose the thermometer whose range includes 22.5 °C and whose smallest division is 0.5 °C or finer (a suitable laboratory/room thermometer). A clinical thermometer (range about 35 °C to 42 °C) cannot read 22.5 °C at all because it lies outside its range. A thermometer whose smallest value is 1 °C cannot show the ‘.5’ part exactly. Only a thermometer that both covers room temperatures and can read in 0.5 °C steps can show 22.5 °C accurately. (Pick the figure that matches these two conditions.)

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 The reading is the mark of the Celsius scale that the top of the liquid column touches. Reading Fig. 7.10, the column lines up with a clear scale mark; the value that matches a definite division (and is not an awkward in-between value like 25.3) is (ii) 27.5 °C. Option (iv) 25.3 °C is unlikely because a thermometer’s smallest division is usually 1 °C or 0.5 °C, so a reading of ‘.3’ cannot be read off exactly. (Confirm against the column position in Fig. 7.10.)

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?

ANSWER She means it on the Fahrenheit scale, i.e. 101 °F. A human body temperature can never reach 101 °C — the temperature of a human being does not normally go above 42 °C, and 101 °C is even hotter than boiling water (100 °C). A fever of 101 °F is only slightly above the normal 98.6 °F, which makes sense for a fever.

Extra Practice Questions

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?

ANSWERThe value 37.0 °C is only the average body temperature of a large number of healthy people, so a perfectly healthy person may have a normal temperature slightly higher or lower than 37.0 °C. Body temperature is influenced by several factors such as age (small children may run slightly higher, older people slightly lower), the time of the day and the person’s activity level. Even so, the temperature of human beings does not normally go below 35 °C or above 42 °C. When measured in the armpit instead of under the tongue, the reading is about 0.5 °C to 1 °C lower than the actual body temperature.

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 bottom of the beaker is always at the same temperature as the water.

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; body temperature stays roughly between 35 °C and 42 °C.
  • 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 score full marks in this chapter

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.

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