Temperature
Thermometers and degrees Celsius.
Temperature
Temperature
What you'll learn
- The difference between heat (energy flow) and temperature (how hot or cold something feels on a scale).
- To read a thermometer in degrees Celsius (°C) — the standard scale in India.
- Normal body temperature (~37 °C), boiling (100 °C), and freezing (0 °C) of water as reference points.
- To connect with NCERT Looking Around 5, Chapter 13 (Blow Hot, Blow Cold).
Key concepts
Level 1 — Heat vs temperature
Verbal: Temperature measures hotness on a scale; heat is energy that moves from hotter to colder objects.
Symbolic: Temperature in °C; heat flows hot → cold until balanced.
| Term | Meaning | Tool |
|---|---|---|
| Temperature | Degree of hotness | Thermometer |
| Heat | Energy transfer | Felt when touching hot pan |
| °C | Celsius scale | Used in weather, medicine |
NCERT link: Looking Around 5, Ch 13 — blowing on hands: warm breath vs cool evaporation.
Level 2 — Reading thermometers and reference points
Verbal: Mercury or alcohol column rises when heated and falls when cooled.
Real-life: Fever check: oral thermometer ~37 °C normal; 38 °C+ may indicate fever — consult an adult/doctor.
| Reference | Temperature (°C) |
|---|---|
| Ice melting (freezing point of water) | 0 |
| Room comfort (approx.) | 25–30 |
| Human body (normal) | ~37 |
| Water boiling (sea level) | 100 |
Worked example
Morning temperature 18 °C; afternoon 32 °C. How much did it rise?
Step 1 — Change = 32 − 18 = 14
Answer: Temperature rose by 14 °C
Why can't you use your hand to measure 60 °C water accurately?
Step 1 — Hand senses hot/cold relatively, not exact degrees.
Step 2 — 60 °C can burn skin — unsafe for touch.
Step 3 — Thermometer gives calibrated reading.
Answer: Skin is not a reliable or safe measuring tool.
Common mistakes
| Mistake | Why it happens | Fix |
|---|---|---|
| Heat and temperature are the same | Everyday language overlap | Temperature = reading; heat = energy moving |
| Thermometer in direct sun = air temperature | Solar heating of device | Shade the thermometer for air temp |
| °C and °F mixed without label | TV/Internet exposure | In India, school science uses °C |
| Body temp exactly 37 °C for everyone always | Textbook average | ~37 °C is average; slight variation normal |
Quick check
- Water freezes at ? °C; boils at ? °C.
- Is heat a thing stored in a spoon, or energy moving?
- Read a diagram: thermometer column at 9 marks above 30 (each mark 1 °C) → ?
- Stretch: Two cups of tea: 80 °C and 60 °C. Which has higher temperature? Which loses heat faster to room air?
Revision tip: Record morning and evening outdoor temperature for one week (weather app or thermometer). Plot a simple line of days vs °C.
Open the Practice tab for graded questions on Temperature.
Key Takeaways (TL;DR)
- What you'll learn
- Key concepts
- Worked example
- Common mistakes
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