This MCQ module is based on: Clinical Thermometer and Measuring Fever
TOPIC 24 OF 46
Clinical Thermometer and Measuring Fever
🎓 Class 6
Science
CBSE
Theory
Ch 7 — Temperature and Its Measurement
⏱ ~14 min
🌐 Language: [gtranslate]
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7.4 The Clinical Thermometer — A Doctor's Friend
Remember Phiban's story from Part 1? When Lambok wanted to measure his body temperature, she did not pick a laboratory thermometer — she used a clinical thermometer. This is the special thermometer made only for measuring the human body's temperature.
A clinical thermometer looks smaller and has a much narrower range of numbers than the lab thermometer. It only needs to measure around the normal body temperature — nothing more.
Clinical thermometer: a thermometer designed to measure the temperature of the human body. Range is usually 35 °C to 42 °C.
Parts of a Clinical Thermometer
- Bulb at one end, holding a liquid (mercury in older types, or a digital sensor in newer ones).
- Capillary tube with a kink (constriction) just above the bulb.
- Scale usually marked in °C and sometimes in °F too.
Why the Kink is So Clever
When the bulb touches the warm body, the mercury expands and rises up the tube. Once you take the thermometer out of the mouth, the mercury would normally want to drop back — but the kink blocks it! So the reading stays fixed until you shake the thermometer firmly. This gives the doctor plenty of time to read the value carefully.
Normal Body Temperature
Normal human body temperature is about 37 °C (which equals 98.6 °F). If the body is hotter than 37.5 °C, we call it a fever.
Activity 7.6 — Measure Your Own Body Temperature L3 Apply
You need: a clinical (preferably digital) thermometer, your notebook.
- Clean the bulb/tip with a tissue.
- Place the bulb under your tongue or in your armpit. Keep still for 1–2 minutes (or until a digital beep).
- Read the value. Note it in your notebook.
- Ask 4–5 friends or family members. Record each person's temperature.
- Look at the table. Are all the numbers exactly 37 °C? Or are they a little different?
Predict: Do you think a baby, a child, and a grown-up will all show exactly the same reading?
Most readings will be between 36.5 °C and 37.5 °C — very close to 37 °C, but not exactly the same. Body temperature changes slightly with time of day, activity and each person. "Normal" is a small range, not one fixed number.
Digital Thermometers — Safer and Smarter
Mercury-based clinical thermometers are slowly being replaced by digital thermometers. Digital ones have a tiny electronic sensor and a small screen that shows the number directly.
Safer
No mercury inside, so there is nothing poisonous even if they fall and break.
Faster
A digital reading comes in about 10–60 seconds with a clear beep.
Easier to read
The number shows up on the screen — no squinting at tiny markings.
No shaking
You do not have to "shake down" a digital thermometer before using it again.
Where to Measure the Temperature
Oral
Under the tongue. Very common, accurate. Keep the mouth closed for 1–2 minutes.
Armpit
Safe for small children. Reading is about 0.5 °C lower than oral.
Ear
Special ear thermometers read in 1 second. Very fast and used in hospitals.
A Warning About Mercury
Mercury is poisonous! Old clinical thermometers contain a silvery liquid called mercury. If the glass breaks:
- Do not touch the mercury with bare hands.
- Never, ever put it in your mouth.
- Tell a grown-up. They will clean it carefully, often using gloves and paper.
- Because of this danger, digital thermometers are now preferred in schools and hospitals.
7.5 Converting Celsius to Fahrenheit (and Back)
Celsius and Fahrenheit are like two different languages for the same temperature. There is a simple way to translate between them.
Formulas:
\[ °F = \frac{9}{5} \times °C + 32 \]
\[ °C = (°F - 32) \times \frac{5}{9} \]
Worked Examples
Example 1: Convert 0 °C to °F.
\( °F = \frac{9}{5} \times 0 + 32 = 0 + 32 = 32\,°F \). So water freezes at 32 °F.
Example 2: Convert 100 °C to °F.
\( °F = \frac{9}{5} \times 100 + 32 = 180 + 32 = 212\,°F \). So water boils at 212 °F.
Example 3: Convert 37 °C (normal body) to °F.
\( °F = \frac{9}{5} \times 37 + 32 = 66.6 + 32 = 98.6\,°F \). That matches what most Indian thermometers also show!
Example 4: Convert 95 °F to °C.
\( °C = (95 - 32) \times \frac{5}{9} = 63 \times \frac{5}{9} = 35\,°C \).
Interactive: °C to °F Converter L3
Type any temperature — we will convert it for you!
Result will appear here…
Competency-Based Questions
Lambok visits Phiban after school. Phiban's temperature is now 38.2 °C. Lambok wants to compare it with the temperature their grandmother measured on an old thermometer in Fahrenheit: 101 °F. She also wonders why her digital thermometer gave the reading so fast.
Q1. What is the range of a clinical thermometer, and why is it so narrow? L2
A clinical thermometer's range is about 35 °C to 42 °C. The human body's temperature stays within this small range, so the thermometer only needs to read this portion of the scale — making each division larger and easier to read precisely.
Q2. Which feature of a clinical thermometer keeps the mercury from falling back into the bulb after the thermometer is removed from the mouth? L1
Answer: C. The kink is a narrow bend in the capillary tube. It blocks the mercury from sliding down until the thermometer is shaken.
Q3. Convert 38.2 °C (Phiban's current temperature) to Fahrenheit. L3
\( °F = \frac{9}{5} \times 38.2 + 32 = 68.76 + 32 = 100.76\,°F \). So Phiban has about 100.8 °F — still a fever.
Q4. Give two reasons why a digital thermometer is preferred over a mercury thermometer. L2
(i) No toxic mercury — safer if the device falls. (ii) The reading appears quickly on a screen with a beep, so it is easy to read even for young children. (Also: no shaking needed, battery-powered, more accurate.)
Q5. Grandma's thermometer shows 101 °F. Convert it to °C. Does Phiban's grandmother have a fever? L4
\( °C = (101 - 32) \times \frac{5}{9} = 69 \times \frac{5}{9} \approx 38.3\,°C \). Yes — 38.3 °C is above 37.5 °C, so grandma has a mild fever.
Assertion – Reason
Assertion (A): A clinical thermometer has a kink in its capillary tube.
Reason (R): The kink lets the mercury drop quickly so the reading changes every second.
Answer: C. The kink actually stops the mercury from falling back — opposite of what R claims.
Assertion (A): Digital thermometers are safer than mercury thermometers.
Reason (R): Mercury is a toxic liquid metal that can harm humans.
Answer: A. Both are true and R explains why digital ones are safer — no mercury means no poisoning risk.
Assertion (A): 0 °C equals 32 °F.
Reason (R): The formula °F = (9/5 × °C) + 32 gives 32 when °C = 0.
Answer: A. Both true; the formula gives the exact value 32.
Frequently Asked Questions — Clinical Thermometer and Measuring Fever
What does the topic 'Clinical Thermometer and Measuring Fever' cover in Class 6 Science?
The topic 'Clinical Thermometer and Measuring Fever' is part of NCERT Class 6 Science Chapter 7 — Temperature and its Measurement. It covers the key ideas of clinical thermometer, digital thermometer, body temperature, fever, 37°C, normal temperature, explained through everyday examples, labelled diagrams and hands-on activities from the NCERT Curiosity textbook. Class 6 students learn simple definitions, see why each idea matters in daily life, and try short experiments and observations. The lesson uses easy language, colourful pictures and small questions so that young learners build a strong base for higher classes and for competency-based questions in CBSE school tests.
Why is 'Clinical Thermometer and Measuring Fever' important for Class 6 NCERT Science?
'Clinical Thermometer and Measuring Fever' is important because it builds the first ideas of science that Class 6 students will use again in Class 7, 8 and beyond. NCERT Chapter 7 — Temperature and its Measurement — introduces clinical thermometer and connects it to things children already see at home, at school and in nature. Learning this topic helps students ask better questions, understand simple news about science, and score well in CBSE tests that use competency-based questions. The chapter also supports NEP 2020 by encouraging curiosity, observation and learning by doing rather than only reading and memorising.
What are the key ideas students should remember from Clinical Thermometer and Measuring Fever?
The key ideas in 'Clinical Thermometer and Measuring Fever' for Class 6 Science are: clinical thermometer, digital thermometer, body temperature, fever, 37°C, normal temperature. Students should be able to say each term in their own words, give one or two easy examples from daily life, and draw a small labelled diagram where needed. A good way to revise is to make flashcards, write a short note in the science notebook, and solve the NCERT in-text and exercise questions of Chapter 7. Linking every idea to something seen at home or school — in the kitchen, garden, playground or sky — makes these ideas easy to remember for unit tests and the annual CBSE examination.
How is Clinical Thermometer and Measuring Fever taught using activities in NCERT Curiosity Class 6?
NCERT Curiosity Class 6 Science teaches 'Clinical Thermometer and Measuring Fever' through an inquiry-based approach using Predict–Observe–Explain activities. Students first make a guess, then try a small experiment with safe, easily available materials, and finally explain what happened and why. This matches the NEP 2020 focus on learning by doing. For Chapter 7 — Temperature and its Measurement — the textbook has hands-on tasks, labelled pictures and thinking questions built for Bloom's Taxonomy Levels 1 to 6. Teachers use these activities, along with competency-based questions (CBQs) and assertion–reason items, to check real understanding instead of only rote learning.
What real-life examples of clinical thermometer can Class 6 students see at home?
Class 6 students can see clinical thermometer at home in many simple ways linked to 'Clinical Thermometer and Measuring Fever'. Kitchens, school bags, playgrounds, the garden and the night sky are full of examples that match NCERT Chapter 7 — Temperature and its Measurement. For example, students can look at food labels, watch changes while cooking, try safe activities with water, magnets or shadows, and observe the Sun, Moon and weather each day. Keeping a small science diary — with the date, what was observed and a quick drawing — turns daily life into a mini science lab. These real-life links make concepts easy to remember and help in answering competency-based questions in CBSE Class 6 Science.
How does 'Clinical Thermometer and Measuring Fever' connect to other chapters of Class 6 Science?
'Clinical Thermometer and Measuring Fever' connects to many other chapters in NCERT Class 6 Science Curiosity. The ideas of clinical thermometer come back when students study related topics like diversity in the living world, food, magnets, measurement, materials, temperature, water, separation, habitats, natural resources and the solar system. For example, what students learn here helps them build mental pictures for later chapters and for Class 7 and Class 8 Science. Teachers often ask cross-chapter questions in CBSE exams to check if students can use what they learned in Chapter 7 — Temperature and its Measurement — in new situations. This linked approach matches the NEP 2020 and NCF 2023 focus on holistic, competency-based learning.
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