Short & Long Question Answers: Temperature and its Measurement | Science for Class 6 PDF Download

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Short Answer Questions:

Q1. What is the role of a thermometer?
Ans: A thermometer is a device used to measure temperature accurately, whether it is for a human body, liquid, or surrounding environment. It helps determine how hot or cold something is by detecting changes in temperature and displaying the result in units like Celsius or Fahrenheit.

Q2. How do digital clinical thermometers differ from mercury thermometers?
Ans: Digital clinical thermometers are more advanced and user-friendly compared to mercury thermometers. They provide faster readings, are easier to read with a digital display, and do not contain toxic mercury, making them safer. Mercury thermometers, on the other hand, use liquid mercury to measure temperature but can be hazardous if broken.

Q3. What does the Celsius scale measure?
Ans: The Celsius scale is a standard unit for measuring temperature, commonly used in scientific and daily applications. It is based on the freezing point of water at 0°C and the boiling point at 100°C under normal atmospheric conditions. This scale is widely used in most countries for weather forecasts, cooking, and scientific research.

Q4. Why should the thermometer’s tip be washed before use?
Ans: The tip of a thermometer should always be washed before and after use to maintain hygiene and prevent the spread of germs or infections. Cleaning ensures that no residual bacteria or contaminants interfere with accurate temperature readings, making the thermometer safe for multiple users.

Q5. How is a clinical thermometer used to measure body temperature?
Ans: A clinical thermometer is placed under the tongue, in the armpit, or rectally for infants. If it is digital, the device beeps or flashes when the reading is ready. In mercury thermometers, the temperature must be read from the mercury level. The reading should be noted carefully before cleaning and storing the thermometer.

Q6. Why can’t a clinical thermometer measure extremely high or low temperatures?
Ans: Clinical thermometers are specifically designed to measure human body temperature within a limited range, usually between 35°C to 42°C. They cannot measure extremely high or low temperatures outside this range because they are not calibrated for industrial, environmental, or scientific purposes, which require specialized thermometers with broader measurement capabilities.

Q7. What is the normal body temperature of a healthy human?
Ans: The normal body temperature of a healthy human is around 37°C (98.6°F). However, this value may slightly vary from person to person and can fluctuate depending on physical activity, time of day, or environmental factors. A temperature higher than 38°C may indicate fever, while a temperature lower than 35°C suggests hypothermia.

Q8. What is the purpose of the Fahrenheit scale?
Ans: The Fahrenheit scale is a temperature measurement system commonly used in the United States and a few other countries. It sets the freezing point of water at 32°F and the boiling point at 212°F under standard atmospheric conditions. This scale is often used in weather reports, household thermometers, and some medical applications.

Q9. Why should laboratory thermometers be handled with care?
Ans: Laboratory thermometers are delicate instruments made of glass and contain either mercury or alcohol-based liquids. If broken, they can cause injury or contamination. Additionally, improper handling can affect their accuracy. To prevent accidents, they should be stored securely, used with caution, and cleaned properly after each use.

Q10. What are the main differences between the Celsius, Fahrenheit, and Kelvin scales?
Ans: The Celsius scale measures temperature based on the freezing and boiling points of water, the Fahrenheit scale is primarily used in the U.S., and the Kelvin scale is used in scientific studies, starting at absolute zero.

Long Answer Questions:

Q1. Explain the process of using a digital clinical thermometer to measure body temperature.
Ans: To measure body temperature using a digital clinical thermometer, first wash the thermometer’s tip with soap and water. Reset the thermometer by pressing the reset button. Place the thermometer under the tongue and close the mouth. 

Wait until the thermometer beeps or flashes a light, indicating that the temperature is ready. After taking the temperature, remove the thermometer and read the display. Clean the thermometer tip again before storing it safely.

Q2. Describe the working principle of a laboratory thermometer and how it is used.
Ans: A laboratory thermometer consists of a glass tube with a bulb at one end, filled with a liquid like mercury or alcohol. As the temperature changes, the liquid expands or contracts, moving along the scale. To use it, immerse the thermometer in the substance being measured, ensuring the bulb doesn’t touch the sides of the container. Hold the thermometer vertically and read the temperature where the liquid column meets the scale.

Q3. Discuss the importance of the Celsius, Fahrenheit, and Kelvin scales in temperature measurement.
Ans: The Celsius scale is widely used around the world for measuring everyday temperatures, including the freezing and boiling points of water. The Fahrenheit scale is primarily used in the United States for weather and medical temperature measurement. The Kelvin scale, which starts at absolute zero, is crucial in scientific studies where precise temperature control is needed, particularly in physics and chemistry.

Q4. How do environmental factors influence the temperature readings of a thermometer?
Ans: Environmental factors such as humidity, air pressure, and altitude can influence temperature readings. For example, the temperature of a body may vary slightly based on the time of day, weather conditions, and the individual’s activity level. Higher altitudes may also lead to slight differences in body temperature readings due to the change in air pressure.