NCERT SOLUTIONS
🌡️ Temperature and Its Measurement
Class 6 Science | Chapter Study Material
Complete Textbook Questions & Answers
📘 Chapter Overview
Learn about temperature, thermometers, Celsius and Fahrenheit scales, laboratory thermometers and clinical thermometers through these NCERT textbook solutions.
Learn about temperature, thermometers, Celsius and Fahrenheit scales, laboratory thermometers and clinical thermometers through these NCERT textbook solutions.
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Question 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
(ii) 37.0°C
(iii) 32.0°C
(iv) 27.0°C
Answer: (ii) 37.0°C
Question 2. 37°C is the same temperature as _______.
(i) 97.4°F
(ii) 97.6°F
(iii) 98.4°F
(iv) 98.6°F
(ii) 97.6°F
(iii) 98.4°F
(iv) 98.6°F
Answer: (iv) 98.6°F
Question 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: Temperature.
(ii) The temperature of ice-cold water cannot be measured by a _______ thermometer.
Answer: Clinical thermometer.
(iii) The unit of temperature is degree _______.
Answer: Celsius.
Question 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
(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
Question 5. Four students used a laboratory thermometer to measure the temperature of water. Who followed the correct way?
(i) Student 1
(ii) Student 2
(iii) Student 3
(iv) Student 4
(ii) Student 2
(iii) Student 3
(iv) Student 4
Answer: (ii) Student 2
Explanation: Student 2 is measuring the temperature correctly because the thermometer bulb is fully immersed in the water and is not touching the sides or bottom of the container. This ensures it only measures the water's temperature.Question 6. Colour to show the red column on the drawings of thermometers as per the temperatures written below.
Answer: This is a diagram activity. Colour the thermometer liquid column up to the specified temperature mark on each drawing.
Question 7. Observe the part of the thermometer shown 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: This is a laboratory thermometer, characterised by its long, narrow tube and a scale that typically ranges beyond the human body temperature range.
(ii) What is the reading of the thermometer?
Answer: 26°C.
(iii) What is the smallest value that this thermometer can measure?
Answer: -10°C.
Question 8. A laboratory thermometer is not used to measure our body temperature. Give a reason.
Answer: A laboratory thermometer is not used to measure human body temperature because:
- It lacks a kink (constriction) to prevent the mercury/liquid from falling automatically.
- It requires upright placement.
- It is designed to measure broader temperature ranges.
- It is inconvenient and potentially unsafe for body temperature measurement.
Question 9. Vaishnavi has not gone to school as she is ill. Her mother has kept a record of her body temperature for three days. Answer the following.
(i) What was Vaishnavi's highest recorded temperature?
(ii) On which day and at what time was her highest temperature recorded?
(iii) On which day did Vaishnavi's temperature return to normal?
Answer: 40.0°C.
(ii) On which day and at what time was her highest temperature recorded?
Answer: Day One at 7 pm.
(iii) On which day did Vaishnavi's temperature return to normal?
Answer: Day Three.
Question 10. If you have to measure the temperature 22.5°C, which of the following three thermometers will you use? Explain.
Answer: We will use thermometer (b).
The smallest division represents 1°C on thermometer (a) and 2°C on thermometer (c). Only thermometer (b) has divisions of 0.5°C, allowing 22.5°C to be read directly and accurately.
Question 11. The temperature shown by the thermometer is:
(i) 28.0°C
(ii) 27.5°C
(iii) 26.5°C
(iv) 25.3°C
(ii) 27.5°C
(iii) 26.5°C
(iv) 25.3°C
Answer: (ii) 27.5°C
Question 12. A laboratory thermometer has 50 divisions between 0°C and 100°C. What does each division of this thermometer measure?
Answer: Each division measures 2°C.
Value of each division = Total temperature range ÷ Total divisions
= 100°C ÷ 50
= 2°C
Therefore, each division represents 2°C.
= 100°C ÷ 50
= 2°C
Question 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: Mark the main numbers at 10°C, 11°C, 12°C and so on up to 20°C. Add one subdivision mark between each degree to represent 0.5°C increments.
| Temperature | Marking |
|---|---|
| 10°C | 10.0°C |
| 10.5°C | 10.5°C |
| 11°C | 11.0°C |
| 11.5°C | 11.5°C |
| 12°C | 12.0°C |
| ... | ... |
| 20°C | 20.0°C |
Question 14. Someone tells you that she has a fever of 101 degrees. Does she mean it on the Celsius scale or Fahrenheit scale?
Answer: She means the temperature on the Fahrenheit scale (°F).
Human body temperature normally ranges between 35°C and 42°C (which corresponds to 95°F to 107.6°F). A body temperature of 101°C would be far above lethal limits.
📖 In-text Questions and Answers
Question 1. Can it always be correctly judged that a person has fever only by touching the person? (Page 123)
Answer: No. It cannot always be correctly judged that a person has a fever only by touch.
- If a person has a normal body temperature and the hand touching them is cold, the person will feel warm.
- If the hand touching the person is warm, a person with a fever may seem to have a normal temperature.
- To accurately determine body temperature, a clinical thermometer must be used.
Question 2. Do small children generally have slightly higher body temperatures as compared to adults? (Page 128)
Answer: Yes. Small children usually have slightly higher body temperatures compared to adults.
This is because their metabolic bodies work harder to grow rapidly, generating more heat.
- Children: 37.0°C to 37.5°C
- Adults: 36.1°C to 37.2°C
Question 3. Do old people, even when healthy, generally have lower body temperatures than young adults? (Page 128)
Answer: Yes. Even healthy older adults generally have lower body temperatures than young adults.
As people age, metabolic processes slow down, producing less body heat. Normal body temperature for older adults is often around 36.2°C to 36.8°C.
Question 4. Can a clinical thermometer be used for measuring the temperature of boiling water? Or for measuring the temperature of ice? (Page 129)
Answer: No. A clinical thermometer cannot be used to measure the temperature of boiling water or ice.
- A clinical thermometer is designed exclusively for human body temperature (35°C to 42°C).
- Boiling water (100°C) far exceeds its scale and may break the glass tube.
- Ice (0°C) is below its lower limit and cannot be measured accurately.
- A laboratory thermometer should be used for measuring extreme temperatures like boiling water or ice.
⭐ Important Concepts
1. Temperature
Temperature determines the hotness or coldness of a system.
2. Normal Human Body Temperature
Approximately 37°C or 98.6°F.
3. Laboratory Thermometer
Usually has a range of -10°C to 110°C.
4. Smallest Division
The value represented by the smallest interval on a thermometer scale.
⚠️ Remember:
A clinical thermometer is not suitable for measuring the temperature of ice or boiling water.
📊 Thermometer Comparison
| Feature | Clinical Thermometer | Laboratory Thermometer |
|---|---|---|
| Purpose | Body temperature | Substances |
| Range in this chapter | 35°C–42°C | -10°C–110°C |
| Kink | Has a kink | No kink |
| Use | Human body | Laboratory experiments |
🚀 Quick Revision
Important facts to remember
- Normal human body temperature = 37°C.
- 37°C = 98.6°F.
- Temperature is measured using a thermometer.
- Unit of temperature = degree Celsius.
- Laboratory thermometer range = -10°C to 110°C.
- 22.5°C can be measured using a thermometer with 0.5°C divisions.
- Each division in a thermometer with 50 divisions between 0°C and 100°C = 2°C.
- 101 degrees of fever refers to Fahrenheit.
❓ Frequently Asked Questions
What is the normal human body temperature?
The normal human body temperature is approximately 37°C or 98.6°F.
Why is a laboratory thermometer not used for body temperature?
It does not have a kink to prevent the liquid column from falling automatically and is not designed specifically for body temperature measurement.
What is the range of a laboratory thermometer?
The usual range given in this chapter is -10°C to 110°C.
Can a clinical thermometer measure boiling water?
No. Boiling water is approximately 100°C, which is beyond the clinical thermometer's range.
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