Temperature and Its Measurement — Class 6 Science NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 6 Science chapter "Temperature and Its Measurement" — 8 important questions with detailed answers for CBSE board exam preparation.
TL;DR: Free step-by-step NCERT solutions for Class 6 Science chapter "Temperature and Its Measurement" — 8 important questions with detailed answers for CBSE…
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NCERT Solutions for Class 6 Science — Temperature and Its Measurement. Step-by-step answers to all 8 textbook questions from this chapter, written for CBSE board preparation and free to use.
Temperature and Its Measurement — All 8 Questions Solved
Q1. What is temperature? How is it measured?
Temperature is the measure of how hot or cold a body is. It is measured using a thermometer, which contains a liquid (usually mercury or alcohol) that expands when heated and contracts when cooled. The expansion or contraction moves the liquid along a scale, showing the temperature reading.
Q2. What are the three main temperature scales?
The three main temperature scales are:
- Celsius (°C): Water freezes at 0°C and boils at 100°C
- Fahrenheit (°F): Water freezes at 32°F and boils at 212°F
- Kelvin (K): Absolute zero is 0 K, water freezes at 273.15 K and boils at 373.15 K
Q3. How does a liquid thermometer work? Explain with an example.
A liquid thermometer contains liquid mercury or alcohol in a glass bulb. When the bulb is placed in a hot body, heat is transferred to the liquid, causing it to expand. The expanding liquid rises up the narrow glass tube marked with temperature numbers. When the bulb is cooled, the liquid contracts and falls down. This movement shows the temperature change.
Q4. What is the difference between heat and temperature?
Temperature is the measure of the average kinetic energy of particles in a body, expressed in degrees. Heat is the energy transferred from a hot body to a cold body due to the temperature difference. Heat flows from higher to lower temperature until thermal equilibrium is reached.
Q5. What safety precautions should be taken while using a thermometer?
Safety precautions when using a thermometer:
- Handle it gently to avoid breaking the glass
- Do not use it to stir liquids
- Do not use it to measure temperatures above its maximum range
- Wash the thermometer with cool water before and after use
- Never hold it too tightly while taking temperature
Q6. What are clinical thermometers and why are they used?
Clinical thermometers are specialized thermometers designed to measure human body temperature. They have a range of 35°C to 42°C. They contain a constriction in the tube that prevents the mercury from falling back when removed from the body, allowing the reading to be taken easily even after removal.
Q7. Explain the concept of 'zero error' in a thermometer.
Zero error is when the mercury level in the thermometer does not read zero when placed in ice water at 0°C. If the mercury is below the zero mark, it is negative zero error. If above, it is positive zero error. Zero error must be recorded and subtracted from or added to all subsequent readings.
Q8. Why is Celsius scale more commonly used than Fahrenheit in science?
The Celsius scale is used more widely in science because:
- It is based on fixed and easily reproducible points: 0°C (freezing of water) and 100°C (boiling of water)
- The scale is simple with exactly 100 divisions between these points
- It is part of the metric system, making calculations easier
- It is the international standard (SI unit) for temperature in science
Temperature and Its Measurement — Practice MCQs with Answers
Attempt these 20 multiple-choice questions after working through the solutions above. Each carries the correct option and the reasoning behind it, so a wrong answer tells you which idea to revisit.
MCQ 1. What is the degree of hotness or coldness of an object called?
- A. Heat
- B. Temperature
- C. Energy
- D. Power
Answer: B. Temperature — Temperature is a measure of the degree of hotness or coldness of an object, indicating the average kinetic energy of its particles.
MCQ 2. Which device is commonly used to measure temperature?
- A. Barometer
- B. Hydrometer
- C. Thermometer
- D. Ammeter
Answer: C. Thermometer — A thermometer is a device specifically designed to measure temperature accurately by utilizing the expansion or contraction of a liquid.
MCQ 3. What is the normal human body temperature in Celsius scale?
- A. 0°C
- B. 25°C
- C. 37°C
- D. 100°C
Answer: C. 37°C — The normal human body temperature is approximately 37°C, which is equivalent to 98.6°F.
MCQ 4. Which type of thermometer is specifically designed to measure the temperature of the human body?
- A. Laboratory thermometer
- B. Clinical thermometer
- C. Weather thermometer
- D. Industrial thermometer
Answer: B. Clinical thermometer — Clinical thermometers are specially designed for measuring human body temperature and have a specific range suitable for this purpose.
MCQ 5. What is the most common unit for measuring temperature in India and for most scientific purposes?
- A. Fahrenheit
- B. Kelvin
- C. Celsius
- D. Rankine
Answer: C. Celsius — Celsius (°C) is the most commonly used unit for measuring temperature in India and for the majority of scientific applications worldwide.
MCQ 6. What is the typical range of a clinical thermometer in Celsius scale?
- A. 0°C to 100°C
- B. -10°C to 110°C
- C. 35°C to 42°C
- D. 90°F to 110°F
Answer: C. 35°C to 42°C — A clinical thermometer has a relatively narrow range, typically from 35°C to 42°C, as human body temperature does not usually fall outside this range.
MCQ 7. Why does a clinical thermometer have a kink or a constriction near the bulb?
- A. To make it stronger
- B. To prevent mercury from falling back into the bulb on its own
- C. To make it easier to read
- D. To keep the mercury warm
Answer: B. To prevent mercury from falling back into the bulb on its own — The kink in a clinical thermometer prevents the mercury level from falling back into the bulb immediately, allowing the user to read the temperature accurately after removing it.
MCQ 8. Which of the following is NOT a precaution to be taken while using a clinical thermometer?
- A. Wash it with an antiseptic solution before and after use
- B. Ensure the mercury level is below 35°C before use
- C. Hold the thermometer by the bulb while reading it
- D. Read the thermometer while keeping the level of mercury along the line of sight
Answer: C. Hold the thermometer by the bulb while reading it — Holding the thermometer by the bulb while reading can transfer heat from your hand to the bulb, leading to an inaccurate temperature reading. It should be held by the stem.
MCQ 9. What is the typical range of a laboratory thermometer?
- A. 35°C to 42°C
- B. 0°C to 100°C
- C. -10°C to 110°C
- D. 90°F to 110°F
Answer: C. -10°C to 110°C — Laboratory thermometers generally have a wider range, typically from -10°C to 110°C, to measure temperatures of various substances and experiments.
MCQ 10. Why is a laboratory thermometer not suitable for measuring human body temperature?
- A. Its glass is too fragile
- B. It uses a different liquid than clinical thermometers
- C. It does not have a kink to hold the mercury level
- D. Its scale is too small for accurate body temperature readings
Answer: C. It does not have a kink to hold the mercury level — A laboratory thermometer lacks the kink found in clinical thermometers, meaning the mercury level would drop immediately upon removal from the body, making it impossible to get an accurate reading.
MCQ 11. What liquid is commonly used inside a liquid-in-glass thermometer due to its high coefficient of expansion and good visibility?
- A. Water
- B. Alcohol
- C. Glycerine
- D. Mercury
Answer: D. Mercury — Mercury is commonly used in thermometers because it expands uniformly with temperature changes, is easily visible, and remains liquid over a wide range of temperatures.
MCQ 12. What would likely happen if you tried to measure the temperature of boiling water (100°C) with a clinical thermometer?
- A. The thermometer would give an accurate reading
- B. The mercury level would drop
- C. The thermometer might break as the temperature is beyond its range
- D. The mercury would freeze
Answer: C. The thermometer might break as the temperature is beyond its range — A clinical thermometer is designed for a narrow range (35°C to 42°C). Measuring boiling water (100°C) would cause the mercury to expand excessively, potentially leading to the thermometer's breakage.
MCQ 13. When two objects, one hot and one cold, are brought into contact, in which direction does heat typically flow?
- A. From cold object to hot object
- B. From hot object to cold object
- C. In both directions simultaneously
- D. No heat flow occurs
Answer: B. From hot object to cold object — Heat naturally flows from an object at a higher temperature (hot) to an object at a lower temperature (cold) until both objects reach thermal equilibrium.
MCQ 14. Why is it important to wash a clinical thermometer with an antiseptic solution before and after use?
- A. To make the mercury expand properly
- B. To ensure accurate readings
- C. To clean the glass for better visibility
- D. To prevent the spread of germs and infections
Answer: D. To prevent the spread of germs and infections — Washing the thermometer with an antiseptic solution is crucial for hygiene, as it helps kill germs and prevents the spread of infections, especially when used by multiple people.
MCQ 15. If a person has a normal body temperature of 37°C, which of the following temperature readings would indicate they have a fever?
- A. 35°C
- B. 36.5°C
- C. 37.5°C
- D. 39°C
Answer: D. 39°C — A normal human body temperature is around 37°C. A temperature of 39°C is significantly higher than normal and indicates a fever.
MCQ 16. What does temperature primarily measure?
- A. The amount of heat energy in an object.
- B. The degree of hotness or coldness of an object.
- C. The weight of an object.
- D. The size of an object.
Answer: B. The degree of hotness or coldness of an object. — Temperature is a measure of the degree of hotness or coldness of an object. It indicates how hot or cold something is, not the total heat energy.
MCQ 17. Which of these units is commonly used to measure temperature in India and for most scientific purposes?
- A. Kilogram (kg)
- B. Celsius (°C)
- C. Fahrenheit (°F)
- D. Litre (L)
Answer: B. Celsius (°C) — Celsius (°C) is the most commonly used unit for measuring temperature in India and for many scientific applications. Fahrenheit (°F) is also a temperature unit but less common in India.
MCQ 18. What is the normal body temperature of a healthy human being in Celsius scale?
- A. 0°C
- B. 37°C
- C. 100°C
- D. 98.6°C
Answer: B. 37°C — The normal body temperature of a healthy human being is approximately 37°C. While 98.6 is a common value, it is on the Fahrenheit scale, not Celsius.
MCQ 19. Which type of thermometer is specifically designed to measure human body temperature?
- A. Laboratory thermometer
- B. Industrial thermometer
- C. Clinical thermometer
- D. Minimum-maximum thermometer
Answer: C. Clinical thermometer — A clinical thermometer is specially designed for measuring human body temperature. It has a narrower range suitable for this purpose.
MCQ 20. What is the typical range of a clinical thermometer?
- A. 0°C to 100°C
- B. -10°C to 110°C
- C. 35°C to 42°C
- D. 90°F to 100°F
Answer: C. 35°C to 42°C — Clinical thermometers have a specific range of 35°C to 42°C (or 94°F to 108°F) because human body temperature rarely falls outside this range.
How to Use These Solutions
Attempt each question yourself first and only then compare with the worked answer. Marks in the CBSE board exam are awarded for the METHOD as much as the final result, so reproduce the steps rather than memorising the last line. Where a solution states a law, a formula or a definition, learn that wording — examiners look for it.
Related practice for this chapter: chapter MCQs, previous-year questions, revision notes and sample papers.