Temperature and its Measurement – Class 6 Science notes, important questions and MCQs

Chapter overview

Temperature tells how hot or cold something is. Touch can mislead us, so we use thermometers.

Thermometers

• Clinical thermometer: 35 °C to 42 °C, has a kink so the reading does not fall quickly; normal body temperature is about 37 °C.
• Laboratory thermometer: about −10 °C to 110 °C; read while the bulb is in the substance.
• Digital thermometers are safer than mercury ones.

Using a thermometer safely

• Wash before and after use; jerk the clinical thermometer to bring the level below 35 °C.
• Keep the eye in level with the reading.
• Scales: Celsius (°C) used in daily life; Kelvin (K) is the SI unit; K = °C + 273.

Key terms

Temperature

measure of how hot or cold something is

Clinical thermometer

thermometer used to measure body temperature

Kink

narrow bend that stops mercury from falling back quickly

Formulas

• Normal body temperature ≈ 37 °C
• K = °C + 273

Important questions with answers

Quick revision

• Clinical range 35–42 °C.
• Normal body temperature 37 °C.
• SI unit of temperature is kelvin.

Exam tips

• Never use a clinical thermometer for hot water — it can break.
• Our hands can be fooled: a cold hand feels lukewarm water as warm.

Practice MCQs

1. Normal human body temperature is about

   1. 30 °C
   2. 37 °C
   3. 42 °C
   4. 100 °C
   Show answer

   Answer: (b) 37 °C. 37 °C.

2. The instrument to measure temperature is a

   1. barometer
   2. speedometer
   3. thermometer
   4. odometer
   Show answer

   Answer: (c) thermometer. Thermometer.

3. The range of a clinical thermometer is

   1. 0–100 °C
   2. 20–50 °C
   3. −10–110 °C
   4. 35–42 °C
   Show answer

   Answer: (d) 35–42 °C. Body temperature range.

4. The SI unit of temperature is

   1. kelvin
   2. degree Celsius
   3. Fahrenheit
   4. joule
   Show answer

   Answer: (a) kelvin. Kelvin.

5. Normal human body temperature is about

   1. 30 °C
   2. 37 °C
   3. 42 °C
   4. 98 °C
   Show answer

   Answer: (b) 37 °C. 98.6 °F.

6. Why does a clinical thermometer have a kink?

   1. to make it look nice
   2. to increase range
   3. to stop mercury from falling back quickly
   4. to measure water temperature
   Show answer

   Answer: (c) to stop mercury from falling back quickly. Reading stays.

7. 25 °C in kelvin is

   1. 248 K
   2. 273 K
   3. 298 K
   4. 25 K
   Show answer

   Answer: (c) 298 K. 25 + 273.

8. The kink in a clinical thermometer

   1. makes it look nice
   2. measures room temperature
   3. stops mercury from falling back on its own
   4. keeps it cold
   Show answer

   Answer: (c) stops mercury from falling back on its own. Keeps the reading.