This MCQ module is based on: Hot and Cold — Introducing the Thermometer
Hot and Cold — Introducing the Thermometer
Phiban's Fever — A Story from Shillong
It was a misty morning in Shillong. Little Phiban woke up feeling tired and warm. His forehead felt burning hot when his mother touched it with her hand. His elder sister Lambok ran to the cupboard and brought out a thermometer. She placed it under Phiban's arm and waited for a minute. The reading showed 39 °C — that is a high fever!
Lambok quickly called the family doctor. After examining Phiban, the doctor confirmed: "Yes, Phiban has a fever. His body is hotter than normal." The whole family was relieved that Lambok had used a thermometer — because a feeling of warmth on the skin can sometimes trick us. A thermometer tells us the exact number, every time.
7.1 Hot or Cold? Can We Trust Our Touch?
Our skin gives us a quick feeling of "hot" or "cold" — but this feeling is not always correct. The same bowl of water can feel cold to one hand and warm to another, if you tricked your hands first! Our sense of touch compares, it does not measure.
You need: three bowls, some hot water (not boiling), some ice-cold water, some water at room temperature.
- Fill bowl A with warm water, bowl B with cold water, bowl C with water at room temperature.
- Dip your left hand in A (warm) and right hand in B (cold) at the same time. Wait one minute.
- Now dip both hands together into bowl C (room temperature). What do your two hands tell you?
7.2 Why We Need a Measuring Device
Knowing "how hot or how cold" matters in many parts of life. We cannot always trust our hands — we need a machine that gives us the exact number. That machine is a thermometer.
7.3 The Laboratory Thermometer
In science class, we use a special thermometer called the laboratory thermometer. It is a long glass tube that can measure a wide range of temperatures — from very cold to very hot liquids we study in experiments.
Parts of a Laboratory Thermometer
- Bulb: the round end at the bottom. It holds a liquid — usually coloured kerosene, alcohol, or mercury.
- Capillary tube: a very thin tube running up the length of the thermometer. The liquid rises and falls here as temperature changes.
- Scale: markings on the side showing numbers in °C (sometimes also °F).
You need: a laboratory thermometer, a beaker of warm water.
- Hold the thermometer vertically. Dip the bulb into the water — make sure it does not touch the bottom or sides of the beaker.
- Wait till the liquid column stops moving.
- Bring your eye exactly level with the top of the liquid column — not above, not below.
- Read and note down the number.
Rules for Using a Thermometer Safely
- Hold the thermometer vertically (straight up).
- Dip only the bulb in the liquid — the bulb should not touch the sides or the bottom of the container.
- Read with your eye level with the liquid surface.
- Do not hold the bulb with your fingers — your body heat will spoil the reading.
- Never shake a laboratory thermometer — it is made of thin glass and can break.
You need: a beaker of warm water, a laboratory thermometer, a stand or clamp.
- Clamp the thermometer so the bulb is fully inside the water but not touching the glass.
- Wait about 30 seconds.
- Read the value at eye-level. Note it in your notebook.
- Pour in a little more hot water. Take the reading again. Did the number go up?
Celsius and Fahrenheit — Two Popular Scales
The scale used most often in India and in science is the Celsius scale (°C). In some countries like the USA, people use the Fahrenheit scale (°F). Both measure the same thing, just with different numbers.
| Event | Celsius (°C) | Fahrenheit (°F) |
|---|---|---|
| Water freezes (ice forms) | 0 °C | 32 °F |
| Room temperature (a nice day) | 25 °C | 77 °F |
| Normal body temperature | 37 °C | 98.6 °F |
| Water boils | 100 °C | 212 °F |
Interactive: Read the Thermometer L3
Hint: The liquid top is between 25 and 50. Look carefully at where it stops.
Competency-Based Questions
Q1. What is a thermometer? L1
Q2. Which of these is the correct way to hold a laboratory thermometer? L2
Q3. Why can't we use only our hands to decide how hot or cold water is? L2
Q4. On the Celsius scale, at what temperature does water freeze and at what temperature does it boil? L1
Q5. In the science trip, one student holds the thermometer by its bulb while reading cup Q. What will go wrong? L4
Assertion – Reason
Assertion (A): A thermometer is needed to measure temperature exactly.
Reason (R): Our hands give the same answer to every person every time.
Assertion (A): While reading a thermometer, the eye should be at the same level as the top of the liquid.
Reason (R): Reading from above or below causes an error called parallax error.
Assertion (A): A laboratory thermometer can measure the temperature of a human body accurately.
Reason (R): The laboratory thermometer has a very wide range (about -10 °C to 110 °C).
Frequently Asked Questions — Hot and Cold — Introducing the Thermometer
What does the topic 'Hot and Cold — Introducing the Thermometer' cover in Class 6 Science?
The topic 'Hot and Cold — Introducing the Thermometer' is part of NCERT Class 6 Science Chapter 7 — Temperature and its Measurement. It covers the key ideas of hot, cold, temperature, thermometer, mercury, Celsius scale, sense of touch, 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 'Hot and Cold — Introducing the Thermometer' important for Class 6 NCERT Science?
'Hot and Cold — Introducing the Thermometer' 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 hot 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 Hot and Cold — Introducing the Thermometer?
The key ideas in 'Hot and Cold — Introducing the Thermometer' for Class 6 Science are: hot, cold, temperature, thermometer, mercury, Celsius scale, sense of touch. 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 Hot and Cold — Introducing the Thermometer taught using activities in NCERT Curiosity Class 6?
NCERT Curiosity Class 6 Science teaches 'Hot and Cold — Introducing the Thermometer' 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 hot can Class 6 students see at home?
Class 6 students can see hot at home in many simple ways linked to 'Hot and Cold — Introducing the Thermometer'. 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 'Hot and Cold — Introducing the Thermometer' connect to other chapters of Class 6 Science?
'Hot and Cold — Introducing the Thermometer' connects to many other chapters in NCERT Class 6 Science Curiosity. The ideas of hot 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.