Temperature and its Measurement
Class 6 · Science
4 ideas in Class 6 Science, explained in plain words, with games and quizzes to practise.
Touch Can Mislead Us
Part of: Hot or cold?
Our skin tells us if something feels hot or cold, but it only compares with what the skin felt just before. Put one hand in cold water and the other in warm water for a minute, then put both in lukewarm water. The cold-soaked hand says warm and the warm-soaked hand says cool, though the water is the same. Temperature, read from a thermometer, is the reliable measure.
Why it matters. Children learn that a fair test needs a measuring tool and not just a feeling. Without this idea, a parent may wrongly guess a fever or a child may believe two people who feel different things about the same water.
Try it in two minutes
- Fill three bowls: cool water, lukewarm water and warm (not hot) tap water.
- Ask your child to keep one hand in the cool bowl and the other in the warm bowl for one minute.
- Now put both hands in the lukewarm bowl. Ask: what does each hand feel? Is the water the same for both?
- Ask: how could we find out the real answer without using our hands?
Try at home. Let your child feel two objects in a room, such as a steel spoon and a wooden spoon, and say which feels colder. Then discuss why both are really at room temperature.
Clinical Thermometer and Body Temperature
Part of: Measuring body temperature
A clinical thermometer is the thermometer used for people. Most homes now have a digital one that beeps when the reading is ready. A healthy person has a temperature close to 37.0 °C, but it can be a little higher or lower depending on age, time of day and activity. Placed under the arm, the reading comes out about 0.5 °C to 1 °C lower than the true body temperature.
Why it matters. Knowing the usual range helps a child understand what a fever reading means. Knowing how to clean and use the thermometer keeps everyone safe and the reading correct.
Try it in two minutes
- Show the digital thermometer to your child. Ask: what do you think it does?
- Wash the tip with soap and water and dry it. Explain why this is done before and after use.
- Measure a family member's temperature and read it aloud. Ask: is it close to 37.0 °C?
- Note the time of day and ask: could the time or activity change the reading?
Try at home. Take your child's temperature in the morning and in the evening for a few days and write the readings in a notebook to see small changes.
Laboratory Thermometer: Range, Smallest Reading and Correct Use
Part of: The laboratory thermometer
A laboratory thermometer is a sealed glass tube with a bulb of coloured liquid at one end and a Celsius scale along the tube. When the temperature rises, the liquid column climbs. The range is the lowest to the highest temperature it can read. The smallest reading is found by dividing the gap between two big marks by the number of small divisions between them. If 10 °C is split into 5 divisions, each one is 2 °C.
Why it matters. Reading a scale carefully is a basic science skill. Using the thermometer wrongly, such as tilting it or letting it touch the bottom, gives wrong numbers, and a wrong number is worse than none.
Try it in two minutes
- Draw a thermometer scale on paper with big marks every 10 and small marks between them.
- Ask your child to count the small divisions between two big marks and work out what each one is worth.
- Talk about the correct way: bulb in the water but not touching the bottom, thermometer upright, eye level with the liquid.
- Ask: why must we read it while it is still in the water?
Try at home. Look at any scale at home, such as a measuring jug or a ruler, and ask your child to work out the smallest value it can show.
Temperature Scales and Their Units
Part of: Scales and units of temperature
Temperature can be written on different scales. The Celsius scale (unit degree Celsius, symbol °C) is common in India. The Fahrenheit scale (°F) is used in some countries, and normal body temperature is 98.6 °F there. The Kelvin scale is used in science and its unit, kelvin (K), is the SI unit of temperature. To change Celsius to kelvin, add 273.15.
Why it matters. Children meet temperatures in weather reports, on medicine labels and in videos from other countries. Knowing the units stops them from reading 98.6 as a dangerously high fever.
Try it in two minutes
- Say 37 °C aloud as thirty-seven degrees Celsius and write it with a space before the unit.
- Tell your child that the same body temperature is 98.6 °F on another scale. Ask: why must we always write the unit?
- Pick a room temperature such as 30 °C and add 273.15 together to get the kelvin value.
- Ask: why would 100 not make sense as a body temperature in °C, but would in °F?
Try at home. Look at the weather report together and ask your child to write today's highest temperature with the correct unit and symbol.
What your child will practise
- Clinical Thermometer and Body Temperature: Jungle Quick Fire (Quick Fire)
- Laboratory Thermometer: Range, Smallest Reading and Correct Use: Lab Sort (Sort It Out)
- Laboratory Thermometer: Range, Smallest Reading and Correct Use: Candy Quick Fir (Quick Fire)
- Temperature Scales and Their Units: Jungle Puzzle (Clue Puzzle)
- Touch Can Mislead Us: Lab Explorer Quest (Collect the Answer)
- Quiz: Clinical Thermometer and Body Temperature (8 questions)
- Quiz: Laboratory Thermometer: Range, Smallest Reading and Correct Use (8 questions)
- Quiz: Temperature Scales and Their Units (8 questions)
- Quiz: Touch Can Mislead Us (8 questions)