Class 6 Science Chapter 7 Extra Questions and Answers – Temperature and its Measurement
Class 6 Science Chapter 7 Extra Questions and Answers for “Temperature and its Measurement” (based on NCERT textbook Curiosity ).
EXTRA IMPORTANT QUESTIONS WITH ANSWERS – Chapter 7 – Temperature and its Measurement
This includes All types of Questions normally asked in school exams, tests, and NCERT exercises.
EXTRA IMPORTANT QUESTIONS & ANSWERS Chapter 7 – Temperature and its Measurement
1. Why can we not rely on our sense of touch to decide whether a body is hot or cold?
Answer:
Because our sense of touch can give wrong ideas. For example, after keeping one hand in warm water and the other in cold water, the same water may feel hot to one hand and cold to the other. Hence, touching is not reliable for judging temperature.
2. What is temperature?
Answer:
Temperature is a reliable measure of the hotness or coldness of a body. The hotter an object is, the higher is its temperature.
3. What is a thermometer?
Answer:
A thermometer is a device used to measure the temperature of a body.
4. Name the three scales of temperature. State their units.
Answer:
- Celsius scale – degree Celsius (°C)
- Fahrenheit scale – degree Fahrenheit (°F)
- Kelvin scale – kelvin (K)
5. Why are digital thermometers preferred over mercury thermometers?
Answer:
Because digital thermometers do not contain toxic mercury, are safer, easier to read, and do not pose environmental hazards if broken.
6. What is the normal body temperature of a healthy person? Give in °C and °F.
Answer:
37.0 °C or 98.6 °F.
7. Why should the digital portion of a thermometer not be dipped in water?
Answer:
Because the digital display and electronic parts can get damaged by water.
8. Why is a clinical thermometer not used to measure boiling water?
Answer:
Because the temperature of boiling water (100 °C) is outside the range of a clinical thermometer (usually 35 °C to 42 °C).
9. What are non-contact thermometers? Why were they commonly used during COVID-19?
Answer:
Non-contact thermometers measure temperature from a distance using infrared sensors.
They were used widely during COVID-19 because they help measure body temperature without touching the person, reducing the risk of infection.
10. What liquid is commonly used in laboratory thermometers?
Answer:
Colored alcohol or mercury.
11. What is meant by the ‘range’ of a thermometer?
Answer:
The range of a thermometer is the lowest and highest temperature it can measure.
12. What is the usual range of a laboratory thermometer?
Answer:
–10 °C to 110 °C.
13. Why should the bulb of a laboratory thermometer not touch the bottom of the beaker?
Answer:
Because the bottom may be hotter or colder than the liquid, giving an incorrect reading.
14. What precautions must be taken while using a laboratory thermometer?
Answer:
- Hold it vertically.
- Bulb should not touch beaker sides or bottom.
- Read temperature while the bulb is still in the liquid.
- Handle carefully as it can break.
- Do not hold by the bulb.
15. Why should we read the temperature while the thermometer is still in the liquid?
Answer:
Because as soon as the thermometer is removed, the liquid column begins to fall and the reading becomes incorrect.
16. Does the temperature of boiling water remain constant? Why?
Answer:
Yes. The temperature of boiling water remains constant at its boiling point because the heat supplied is used to convert water into steam, not to increase temperature.
17. Does the temperature of melting ice change while it melts?
Answer:
No, it remains constant at 0 °C until all ice melts.
18. What is the smallest division of a thermometer? Explain how to find it.
Answer:
Smallest division = (Difference between two major marks) ÷ (Number of small divisions between them).
Example: If 10 °C is divided into 10 parts → each division = 1 °C.
19. Why is a laboratory thermometer unsuitable for measuring human body temperature?
Answer:
Because it does not have a “kink” and its range is large. The reading falls instantly, giving incorrect values for body temperature.
20. What is air temperature? Where is it seen?
Answer:
Air temperature is the temperature of the atmosphere around us.
It is seen in weather reports as maximum and minimum temperatures of the day.
21. What instrument is used to measure room temperature?
Answer:
A room thermometer.
22. What is the SI unit of temperature? Why is it used in scientific work?
Answer:
Kelvin (K).
It is used because it is an absolute scale starting from absolute zero and is convenient for scientific calculations.
23. Convert 37 °C to Kelvin.
Answer:
K = °C + 273.15
= 37 + 273.15
= 310.15 K
24. Why does every person not have exactly 37 °C body temperature?
Answer:
Because body temperature varies due to age, activity level, time of day, environmental factors, and health conditions. 37 °C is only the average normal value.
25. Why is mercury not used in modern clinical thermometers?
Answer:
Because mercury is toxic, difficult to dispose safely, and hazardous when thermometers break.
26. What changes occur in the liquid column of a thermometer when temperature increases?
Answer:
The liquid expands and rises in the tube to show a higher temperature.
27. At what temperature is the human body in danger?
Answer:
Generally, body temperature above 42 °C or below 35 °C is dangerous.
28. What are maximum and minimum temperature readings?
Answer:
They are the highest and lowest air temperatures recorded in a day.
29. What is absolute zero?
Answer:
Absolute zero is the lowest possible temperature, equal to –273.15 °C or 0 K.
30. Why is the degree sign (°) not used with Kelvin?
Answer:
Because kelvin is an SI unit and not a degree-based scale.
31. What factors can change room temperature during the day?
Answer:
Sunlight, ventilation, weather changes, human activity, and use of fans or heaters.
32. What precautions should you follow before measuring body temperature with a digital thermometer?
Answer:
- Wash hands.
- Wash the tip of the thermometer.
- Read user instructions.
- Ensure the digital part does not get wet.
33. What does Anna Mani’s work teach us about scientific instruments?
Answer:
Her work shows the importance of accurate measurement tools for weather and energy studies and reducing dependence on other countries.
34. Why does water cool slowly after boiling?
Answer:
Because water has high heat capacity, which means it holds heat for a longer time.
35. Why must we keep the thermometer vertical while reading temperature?
Answer:
To avoid parallax error and get an accurate reading.
36. Why do smaller children sometimes have slightly higher body temperatures?
Answer:
Because their metabolism is faster than adults.
37. Why does a person feel cold after coming out of warm water?
Answer:
Because temperature difference causes heat to flow from the body to the cooler air.
38. Why does temperature vary during the day?
Answer:
Due to changing sunlight, weather conditions, and environmental factors.
39. A thermometer shows 38 °C. Is the person having fever?
Answer:
Yes. 38 °C is higher than the normal (37 °C).
40. Why do digital thermometers give sound or light signals?
Answer:
To indicate that the reading is completed and stable.