Temperature and its Measurement
Is it hot or cold, and exactly how hot? This Class 6 Curiosity chapter explains that temperature is a measure of how hot or cold something is, why our senses are not reliable for judging it, how a thermometer measures it in degrees Celsius, and what the normal temperature of the human body is.
Learning objectives
- Explain what temperature means.
- State why senses alone are unreliable.
- Use a thermometer and its unit.
- Recall normal body temperature.
Key concepts
What is temperature?
Temperature is a measure of how hot or cold an object is. A hotter object has a higher temperature and a colder one a lower temperature. Temperature is a definite, measurable quantity, not just a feeling.
Why senses are unreliable
Our sense of touch can mislead us about temperature. The same lukewarm water can feel warm to a hand that was in cold water and cool to a hand that was in warm water. Because of this, we need an instrument to measure temperature accurately.
The thermometer
A thermometer measures temperature. A clinical thermometer measures body temperature, while a laboratory thermometer measures the temperature of other things. To read it, we look at the level on the scale with the eye held directly in line, and the clinical thermometer is washed before and after use.
Units and body temperature
Temperature is commonly measured in degrees Celsius (°C). The normal temperature of the human body is about 37 °C. A reading clearly above this usually means the person has a fever, which is why a clinical thermometer's scale is marked around the normal value.
Key definitions
- Temperature
- A measure of how hot or cold an object is.
- Thermometer
- An instrument used to measure temperature.
- Clinical thermometer
- A thermometer used to measure body temperature.
- Degree Celsius
- The common unit of temperature, written °C.
Solved examples
Q1. What is the normal temperature of the human body?
Solution: About 37 °C.
Q2. Why can't we rely on touch to judge temperature?
Solution: Because the same object can feel different to hands at different temperatures.
Q3. Which thermometer measures body temperature?
Solution: A clinical thermometer.
Common mistakes to avoid
- Believing touch alone gives an accurate temperature.
- Confusing a clinical thermometer with a laboratory one.
- Forgetting to wash a clinical thermometer before and after use.
- Reading the thermometer level from an angle.
Temperature and its Measurement — MCQ Quiz
10 questions with instant feedback. Use number keys 1–4 to answer.
Temperature is a measure of:
Practice questions
Short answer
What is temperature?
A measure of how hot or cold an object is.
What is the unit of temperature?
The degree Celsius (°C).
What is normal body temperature?
About 37 °C.
Long answer
Why do we need a thermometer instead of judging temperature by touch?
Our sense of touch only tells us whether something feels warmer or colder than our skin, and it can be fooled. If one hand has been in cold water and the other in warm water, the same bowl of lukewarm water feels warm to one hand and cool to the other — yet it has a single, definite temperature. Because touch is relative and unreliable, we use a thermometer, which gives the same accurate reading every time and lets different people agree on exactly how hot or cold something is.
Describe the thermometer, its unit, and normal body temperature.
A thermometer is an instrument that measures temperature. A clinical thermometer is used for the human body, while a laboratory thermometer is used for other objects and liquids. Temperature is commonly measured in degrees Celsius (°C), and to read a thermometer accurately we look at the level on its scale with the eye held directly in line. The normal temperature of the human body is about 37 °C; a clinical thermometer's scale is marked around this value, and a reading clearly above it usually indicates a fever. For hygiene, a clinical thermometer is washed before and after each use.
HOTS (Higher Order Thinking)
After holding ice, a cup of warm milk feels very hot, but to another person it feels just warm. What does this show about touch?
It shows touch is relative and unreliable for measuring temperature, since the same milk feels different depending on the hand's previous condition.
Why is a separate clinical thermometer used for the body instead of a laboratory one?
Because the body's temperature stays in a narrow range around 37 °C, and a clinical thermometer is designed with a scale focused on that range for accurate, convenient readings.
Quick revision
Revision notes
- Temperature = how hot or cold something is (measurable, not just a feeling).
- Touch is relative and unreliable; use a thermometer.
- Unit: degree Celsius (°C); clinical thermometer for the body.
- Normal body temperature ≈ 37 °C; higher usually means fever.
Key takeaways
- Temperature is a measurable quantity, not a feeling.
- Thermometers measure it accurately in °C.
- Normal body temperature is about 37 °C.
Frequently asked questions
What is temperature?
A measure of how hot or cold an object is.
What unit is temperature measured in?
Degrees Celsius (°C).
What is the normal temperature of the human body?
About 37 °C.