Chapter 7: Temperature and its Measurement (Physics)
Answers to all "Let us enhance our learning" questions of Chapter 7, Temperature and its Measurement (NCERT Class 6 Science, Curiosity, 2026-27): clinical and laboratory thermometers, Celsius and Fahrenheit scales, reading a thermometer correctly, and normal body temperature. All 14 questions are answered, with the key answer highlighted.
Normal body temperature ≈ 37.0 °C (98.6 °F). A clinical thermometer usually reads 35 °C to 42 °C; a laboratory thermometer usually −10 °C to 110 °C. While measuring, keep the laboratory thermometer upright, with its bulb fully in the liquid but not touching the bottom or sides, and read it with your eye level with the top of the liquid column.
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 ___.
Solution
(i) temperature (ii) clinical (its range starts at 35 °C) (iii) Celsius (°C)
Four students used a laboratory thermometer to measure the temperature of water (Fig. 7.6). Who followed the correct way for measuring temperature? (i) Student 1 (ii) Student 2 (iii) Student 3 (iv) Student 4
Solution
(iii) Student 3. Student 3 holds the thermometer upright, with the bulb fully dipped in the water and not touching the bottom or the sides of the beaker. Student 1 holds it slanting, and in the others the bulb either touches the beaker or is not properly in the water, which gives a wrong reading.
(iii) Student 3: thermometer upright, bulb fully in the water without touching the beaker.
Observe the part of the thermometer shown in Fig. 7.8. (i) What type of thermometer is it? (ii) What is the reading? (iii) What is the smallest value that this thermometer can measure?
Solution
(i) A laboratory thermometer (its scale starts below 0 °C, at −10 °C).
(ii) The red column ends a little after the 25 °C mark: about 26 °C.
(iii) There are 10 divisions between 0 and 10, so each division is 1 °C.
(i) Laboratory thermometer (ii) about 26 °C (iii) 1 °C
A laboratory thermometer is not used to measure our body temperature. Give a reason.
Solution
A laboratory thermometer has no kink near the bulb, so the mercury or alcohol level starts falling as soon as it is taken out of the mouth or armpit; we cannot read it properly.
It is long and not designed to be kept under the tongue; and its range (−10 °C to 110 °C) with 1 °C divisions is too coarse for body temperature, where small changes (like 0.1 °C) matter.
A clinical thermometer is made for this purpose.
The level in a laboratory thermometer falls as soon as it is removed from the body (no kink), and it is not made to be kept in the mouth; a clinical thermometer is used instead.
Vaishnavi's body temperature was recorded for three days (Table 7.4). (i) What was her highest recorded temperature? (ii) On which day and at what time was it recorded? (iii) On which day did her temperature return to normal?
Solution
(i) 40.0 °C
(ii) On Day One at 7 pm.
(iii) On Day Three: her temperature came down to 37.0 °C at 4 pm (and went slightly below, which is still normal).
(i) 40.0 °C (ii) Day One, 7 pm (iii) Day Three (37.0 °C at 4 pm)
If you have to measure the temperature 22.5 °C, which of the three thermometers in Fig. 7.9 will you use? Explain.
Solution
Thermometer (b). It has 20 divisions between two 10 °C marks, so each division is 0.5 °C, and 22.5 °C falls exactly on a mark. Thermometer (a) has 1 °C divisions and (c) has 2 °C divisions, so with them 22.5 °C can only be guessed.
(b): its smallest division is 0.5 °C, so it can show 22.5 °C exactly.
Komal tells you that she has a fever of 101 degrees. Does she mean it on the Celsius scale or Fahrenheit scale?
Solution
Fahrenheit. Normal body temperature is 98.6 °F (37 °C), so 101 °F is a fever (about 38.3 °C). 101 °C is impossible for a living person (it is hotter than boiling water).
The Fahrenheit scale: 101 °F is a fever; 101 °C is hotter than boiling water.
