All questions of Temperature and its Measurement for Class 6 Exam

On the Kelvin scale, the boiling point of water is 373.15 K.

Understanding Temperature Differences
When we talk about the temperatures of different bodies, the concept of temperature is crucial in understanding how heat is distributed among objects.
Observation of Temperature Variations
The correct answer is option 'B': Some bodies have higher temperatures than others. This observation is fundamental in science and can be explained through several key points:
Heat and Temperature
- Temperature is a measure of how hot or cold an object is.
- It indicates the average kinetic energy of the particles in a substance; the higher the temperature, the more energy the particles have.
Different Materials, Different Temperatures
- Different materials absorb and release heat differently. For example, metal feels colder than wood at the same temperature because metal conducts heat away from your skin more efficiently.
- The same amount of heat can raise the temperature of one material more than another due to differences in specific heat capacity.
Measurement Tools
- Temperature can be measured using various instruments like thermometers, which provide a numerical value to the sensation of warmth or coldness.
- The ability to measure temperature allows us to quantify these differences between bodies.
Real-World Examples
- In everyday life, we can observe this when touching ice (which feels cold) compared to a hot cup of coffee. They have significantly different temperatures.
- Even in the environment, the sun heats some surfaces more than others, leading to variations in temperature.
In summary, recognizing that some bodies have higher temperatures than others is essential to understanding thermal dynamics and the behavior of materials in our world.

During the COVID-19 pandemic, infrared (non-contact) thermometers became widely used for several key reasons. 

Minimizing contact and reducing disease spread: Unlike traditional thermometers that require physical contact with the body, infrared thermometers can measure temperature from a distance. This was crucial for minimizing the risk of COVID-19 transmission between individuals during temperature screenings, particularly in public places like airports, hospitals, and workplaces.Speed and efficiency: Infrared thermometers provide rapid temperature readings, allowing for quick screening of large numbers of people without causing significant delays.Ease of use: These thermometers are relatively simple to operate, making them suitable for use by non-medical personnel in various screening settings. 

In essence, infrared thermometers offered a practical and relatively safe solution for conducting temperature screenings during the pandemic, helping to identify individuals with fever (a common symptom of COVID-19) while mitigating the risk of viral transmission. 

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Mercury is often used in laboratory thermometers due to its ability to expand uniformly with temperature changes. Alcohol is also used, usually colored red for visibility.

A clinical thermometer is designed for measuring human body temperature in Celsius (°C) or Fahrenheit (°F).

The Kelvin (K) scale is commonly used in science because it starts at absolute zero.

Understanding Water Boiling Point
Water boils at a specific temperature depending on the scale used to measure temperature. In the Celsius scale, water boils at 100°C.
Why Does Water Boil at 100°C?
- Boiling Point Definition: The boiling point of a liquid is the temperature at which it changes from a liquid to a gas. For water, this occurs when it reaches 100°C at standard atmospheric pressure (1 atmosphere or 101.3 kPa).
- Molecular Activity: At this temperature, water molecules have enough energy to overcome the forces holding them together in the liquid state. As they gain energy, they move faster and eventually break free to become steam (gas).
Comparison with Other Temperatures
- 0°C: This is the freezing point of water, where it changes from liquid to solid.
- 32°C: This is equivalent to 0°C in the Fahrenheit scale, not relevant for boiling.
- 273°C: This temperature is not standard for boiling water; it relates to absolute zero in Kelvin.
Conclusion
In summary, the correct answer to the question regarding the boiling point of water on the Celsius scale is 100°C. This is a fundamental concept in understanding phase changes in water, which is crucial for various scientific and practical applications.

Understanding the Standard SI Unit of Temperature
The standard SI (International System of Units) unit of temperature is the Kelvin. Here’s a detailed explanation:
What is Kelvin?
- The Kelvin scale is an absolute temperature scale named after the Scottish physicist William Thomson, 1st Baron Kelvin.
- It starts at absolute zero, the point at which all molecular motion ceases, defined as 0 K, which is equivalent to -273.15 degrees Celsius.
Why Kelvin is the Standard Unit?
- Absolute Scale: The Kelvin scale is an absolute scale, making it essential in scientific contexts because it provides a direct measure of thermal energy.
- Direct Relation to Energy: The temperature in Kelvin is directly proportional to the average kinetic energy of particles in a substance, which is crucial for calculations in thermodynamics and physical chemistry.
Comparison with Other Units
- Celsius (°C): Although widely used for everyday temperature measurements (e.g., weather), Celsius is not an absolute scale since it is based on the freezing and boiling points of water.
- Fahrenheit (°F): Primarily used in the United States, Fahrenheit is also not an absolute scale and is less convenient for scientific calculations.
- Joule (J): This is a unit of energy, not temperature, and is unrelated to the measurement of thermal temperature.
Conclusion
The Kelvin is the preferred unit in scientific contexts, ensuring consistency and accuracy in temperature measurements across various fields of study.

Mercury is a toxic substance, making mercury thermometers hazardous. Digital thermometers are safer and more convenient.

Body temperature can be influenced by age, activity level, and time of day, but not by eye color.

Digital thermometers use electronic sensors to measure and display the temperature digitally.

Heat always flows from a hotter object to a colder one until both objects reach thermal equilibrium.

Anna Mani was an Indian scientist who developed weather measurement tools and reduced the need for imported equipment.

The capillary tube contains a liquid column that expands or contracts with temperature changes, indicating the temperature reading.

Temperature indicates how much heat energy an object has, determining whether it is hot or cold.

Different materials conduct heat differently, which can trick our sense of touch into perceiving incorrect temperatures.

Laboratory thermometers are used in scientific experiments to measure the temperature of liquids, gases, or solids.

A thermometer is specifically designed to measure temperature accurately.

The normal body temperature of a healthy adult is around 37°C or 98.6°F.