🌡️ Temperature and Its Measurement – A Cool & Hot Journey of Science!

Class 6 CBSE Science Curiosity temperature and it's measurement

🔥 Introduction – Why Temperature Matters in Our Life

Imagine coming home on a summer afternoon, feeling sweaty and hot, and then sipping a glass of chilled water from a matka (earthen pot). Instantly refreshing, right? On another day, you may shiver during winter and rush for a cozy blanket. All these experiences are linked to one magical idea – Temperature!

Temperature tells us how hot or cold something is. From checking our body during fever, to forecasting weather, to cooking food, to studying stars—temperature plays a key role everywhere. Without temperature measurement, life would be full of guesswork.

So, in this post, let’s dive deep into the fascinating world of temperature and its measurement. Get ready—this is going to be a mix of science, fun facts, and simple activities you can even try at home!

🧊 7.1 Hot or Cold? – Can We Trust Our Hands?

We often decide whether something is hot or cold just by touching it. But, is our sense of touch reliable? Let’s see.

👉 Try this simple activity:

Take three containers. Fill them with warm water (A), normal tap water (B), and ice-cold water (C).
Dip your right hand in A and left hand in C for about 1–2 minutes.
Now, put both hands in B.

🤯 What did you feel?
Your right hand (used to warm water) feels B is cold, while your left hand (used to cold water) feels B is warm.
Conclusion? Our hands can confuse us. That’s why we need a scientific tool—thermometer—to measure temperature accurately.

💡 Did you know?
Wrong measurements can be more harmful than no measurements. That’s why famous Indian physicist Anna Mani, also called the Weather Woman of India, once said:
“Wrong measurements are worse than no measurements at all.”

🌡️ 7.2 What is Temperature?

Temperature is a reliable measure of how hot or cold a body is.

A hotter body = higher temperature.
A colder body = lower temperature.

And the instrument that measures it? The Thermometer.

There are mainly two types you’ll often see:

Clinical Thermometers – used to measure human body temperature.
Laboratory Thermometers – used for experiments and scientific work.

👩‍⚕️ 7.3.1 Clinical Thermometer – Your Health Checker

Whenever you feel feverish, what’s the first thing your parents do? Take out a thermometer! That small device is called a clinical thermometer.

Modern ones are usually digital clinical thermometers:
✔ Easy to read
✔ Run on small batteries
✔ Safer than old mercury thermometers

👉 Why not mercury anymore?
Mercury is poisonous and dangerous if a thermometer breaks. That’s why digital thermometers are now preferred—they use heat sensors and give readings quickly.

📏 Temperature Scales in Clinical Thermometers

Celsius Scale (°C) – commonly used in India.
Fahrenheit Scale (°F) – common in the USA.
Normal human body temperature:
- 37.0 °C = 98.6 °F.

💡 Fun Fact:
During the COVID-19 pandemic, special infrared thermometers were used. These could measure body temperature without touching—just by pointing them at the forehead! Cool, right?

🌡️7.3 Measuring Temperature

🩺 Using a Digital Clinical Thermometer

Here’s how you can safely measure body temperature using a digital thermometer:

Wash your hands and clean the tip of the thermometer with soap and water.
Reset the thermometer by pressing the button.
Place it under your tongue and close your mouth.
Wait till you hear a beep sound or see a light flash.
Read the number on the display.
Clean the thermometer again before putting it back.

💡 Pro Tip: For small children or elderly people, the thermometer can be placed in the armpit. But remember, the reading will be about 0.5–1 °C lower than the actual body temperature.

🧍‍♂️ What is Normal Body Temperature?

We usually say the normal human body temperature is 37 °C (98.6 °F). But in reality, not everyone’s body shows exactly this number.

A healthy person may have a body temperature slightly higher or lower.
Temperature can vary with age, time of the day, or physical activity.
Generally, the body temperature stays between 35 °C to 42 °C.

👉 Try This!
Measure your temperature at different times of the day for a week. Record your results. You’ll see that your body temperature is not the same all the time!

💡 Did you know?

Children often have a slightly higher body temperature than adults.
Old people usually have a lower body temperature, even when they are healthy.

📏 7.3.2 Laboratory Thermometer – Science’s Helper

In your school lab, you may have seen a long glass thermometer with a bulb at one end. That’s the laboratory thermometer.

The bulb contains alcohol (red-colored) or mercury.
The liquid rises or falls depending on the temperature.
The Celsius scale is marked along the tube for readings.

👉 Example: A typical lab thermometer has a range from –10 °C to 110 °C.
This makes it suitable for experiments like measuring the temperature of ice, boiling water, or chemical reactions.

⚠️ Precautions for Laboratory Thermometer:

Handle carefully—it’s fragile!
Never hold it by the bulb.
While measuring, keep it vertical and make sure the bulb doesn’t touch the bottom or sides of the container.
Always read the temperature with your eyes at the same level as the liquid column.

💡 Fun Fact:
Did you know boiling water does not always boil at exactly 100 °C? In places at high altitudes (like Shillong or Shimla), it may boil around 97–98 °C because of lower air pressure!

🧊 Activity – Measure and Compare

Place a lab thermometer in crushed ice and another in boiling water.
Note the temperatures.
Wait for some time and check again.

You’ll observe:

The temperature of boiling water remains constant while it boils.
The temperature of ice remains constant while it melts.

👉 This is why we say that during melting or boiling, the temperature of a substance does not change even though heat is continuously supplied!

🌬️ 7.3.3 Air Temperature – Weather’s Secret

When you watch the news or check your weather app, you often see two values: Maximum temperature and Minimum temperature.

But how are these measured? 🤔

A room thermometer (like the one in your classroom or doctor’s clinic) shows the approximate room temperature.
For weather reports, special thermometers measure air temperature at different times of the day.

👉 Try This Activity:

Record the maximum and minimum temperature from weather reports for 10 days.
Write them in a table.
Notice how the temperature rises in summer and falls in winter.

💡 Did you know?
India’s famous scientist Anna Mani, known as the Weather Woman of India, developed many weather instruments. Her inventions helped India become self-reliant in measuring weather and even supported renewable energy studies!

📊 7.4 Temperature Scales – Celsius, Fahrenheit & Kelvin

There are three important temperature scales used across the world:

Celsius Scale (°C)
- Used in India and most countries.
- Normal human body temperature = 37 °C.
Fahrenheit Scale (°F)
- Common in the USA.
- Same normal body temperature = 98.6 °F.
Kelvin Scale (K)
- Used in science and research.
- SI unit of temperature.
- Formula: Kelvin = Celsius + 273.15
- Example: 37 °C = 310.15 K

⚠️ Important Rule:

We write °C and °F with the degree sign, but Kelvin (K) is written without it.
Always leave a space between the number and the unit (like 37 °C, not 37°C).

💡 Fun Fact:
All these scales are named after great scientists:

Anders Celsius
Daniel Fahrenheit
Lord Kelvin

🌌 Mind-Blowing Temperature Facts

The core of the Sun reaches nearly 15 million °C! ☀️
The coldest temperature possible is called absolute zero (–273.15 °C or 0 K). At this point, particles stop moving completely! ❄️
Different planets in our solar system have very different average temperatures. For example:
- Mercury (closest to the Sun): Extremely hot during the day.
- Neptune (farthest from the Sun): Freezing cold.

👉 Challenge Yourself:
Make a table of planets, their distance from the Sun, and their average temperature. Check if the farther planets are always colder—or are there exceptions?

✅ Summary – What We Learned

Temperature tells us how hot or cold something is.
Clinical thermometers are used for human body temperatures.
Laboratory thermometers are used in experiments, usually from –10 °C to 110 °C.
Normal human body temperature is about 37 °C (98.6 °F).
Three scales of temperature: Celsius (°C), Fahrenheit (°F), Kelvin (K).
SI unit of temperature = Kelvin.
Temperature affects our daily life, weather forecasts, science, and even space studies.

🌈 Stay Curious, Stay Cool (and Warm!)

Temperature may sound like a simple idea, but it is deeply connected to health, science, weather, and the universe itself. Next time you sip hot coffee, enjoy ice cream, or check the weather report, remember—you are experiencing the science of temperature in action!

So, keep observing, keep experimenting, and stay curious. Science is all around you, waiting to be explored. 🌍✨