NCERT Class 6 Science Chapter 7 Temperature and its Measurement Important Extra Questions and Answers

Very Short Answer Type Questions

Question 1.
What is a reliable measure of hotness or coldness of a body?
Answer:
Temperature.

Question 2.
What device measures temperature?
Answer:
Thermometer.

Question 3.
Name two types of thermometers.
Answer:
Clinical and laboratory thermometers.

Question 4.
What scale is commonly used in clinical thermometers?
Answer:
Celsius scale.

Question 5.
What is the normal temperature of a healthy human body on Celsius and on Fahrenheit scale?
Answer:
37.0 °C, 98.6 °F.

 

Question 6.
What substance was traditionally used in thermometers but is now avoided due to toxicity?
Answer:
Mercury.

Question 7.
Which type of thermometer uses heat sensors to measure temperature?
Answer:
Digital thermometer.

Question 8.
How much lower is the temperature measured in the armpit compared to the actual body temperature?
Answer:
About 0.5 °C to 1 °C lower.

Question 9.
What is the unit of temperature in the Kelvin scale?
Answer:
Kelvin (K).

Question 10.
Can a clinical thermometer measure the temperature of boiling water?
Answer:
No. Boiling water has a temperature of 100°C, while the clinical thermometer has a range of 35 °C to 42 °C only.

Question 11.
What is the temperature range of a typical laboratory thermometer?
Answer:
10 °C to 110 °C.

Question 12.
What liquid is commonly used in laboratory thermometers?
Answer:
Coloured alcohol (usually red) or mercury.

Question 13.
At what temperature does the Celsius scale mark the boiling point of water and the freezing point of water?
Answer:
100 °C, 0 °C.

Question 14.
What is the smallest value a laboratory thermometer can read according to the text?
Answer:
-10°C.

Question 15.
What is the SI unit of htemperature?
Answer:
Kelvin (K).

Question 16.
What should be done to the digital thermometer before and after use?
Answer:
Wash the tip with soap and water.

Question 17.
If the temperature of an object increases by 10º C, by how many degrees Fahrenheit does it increase?
Answer:
An increase of 10º C is equivalent to an increase of 18º F

Question 18.
Why does a thermometer placed in a cup of hot water eventually stop rising in temperature?
Answer:
When a thermometer is placed in a cup of hot water, it absorbs heat from the water until it reaches thermal equilibrium. At this point, the thermometer’s temperature is equal to the temperature of the water, and it stops rising.

Short Answer Type Questions

Question 1.
Why is it important to measure temperature accurately?
Answer:
Accurate temperature measurement is important because wrong measurements can lead to incorrect conclusions. Inaccurate measure of body temperature may lead to suggest a fever when there is no fever and when there is fever it may suggest no fever.

Question 2.
How does a digital clinical thermometer work?
Answer:
A digital clinical thermometer measures temperature using heat sensors and displays the temperature digitally. It runs on batteries and provides an easy- to-read digital display. There is no risk in using a digital clinical thermometer that was associated with the mercury thermometers.

Question 3.
What is the normal range of human body temperature, and why might it vary?
Answer:
The normal range of human body temperature is around 37.0 °C but can vary slightly due to factors like age, time of day, and activity level. A perfectly healthy person’s temperature might be a bit higher or lower than 37.0 °C.

Question 4.
Why is it necessary to wash the tip of the thermometer before and after use?
Answer:
Washing the tip of the thermometer before and after use helps prevent the spread of germs and ensures accurate readings. It is essential for maintaining hygiene, especially when measuring the temperature of different individuals.

Question 5.
How do non-contact thermometers work, and what are their benefits?
Answer:
Non-contact thermometers, or infrared thermometers, measure temperature from a distance using infrared sensors. They reduce the risk of spreading infections and are particularly useful in medical settings for quick, safe temperature checks.

 

Question 6.
What did people use to detect fever before thermometers were developed?
Answer:
Before thermometers, people used to detect fever by checking the pulse rate, as fever affects it. However, this method was not very reliable since conditions other than fever could also influence the pulse rate.

Question 7.
How do you measure temperature using a laboratory thermometer? What precautions should be taken when using a laboratory thermometer?
Answer:
To measure temperature with a laboratory therfnometer, immerse the bulb in the substance without touching the sides or bottom of the container. Hold the thermometer vertically and read the temperature while it is still immersed. Ensure your eye level is in line with the liquid column in the thermometer.

Question 8.
How is the Kelvin scale related to the Celsius scale?
Answer:
The Kelvin scale is related to the Celsius scale by the formula:
Temperature in Kelvin = Temperature in Celsius + 273.15.

Question 9.
What is the role of weather stations in measuring air temperature?
Answer:
Weather stations monitor air temperature along with other parameters to gather data used for weather forecasting. This data collection helps predict weather patterns and informs the public about daily temperature variations and climate trends.

Question 10.
What smallest value of temperature can we measure on a laboratory thermometer?
Answer:
Different laboratory thermometers give different measures of the smallest value of temperature. This depends on the scale markings on the thermometer. In some thermometers 5 small lines are marked between any 10 (10 – 20 or 20 – 30 degrees) degrees. The smallest value of temperature of 2 degrees is measured on these. When a thermometer has 20 small lines between any 10 degrees, The smallest value of temperature of 0.5 degrees is measured on these.

Question 11.
Explain why a digital thermometer is considered safer and more accurate than a mercury thermometer.
Answer:
A digital thermometer uses heat sensors to provide a digital readout, eliminating the risk of mercury exposure and providing a precise, easy-to-read measurement. It is less prone to reading errors like mercury thermometers.

Question 12.
How does the sense of touch sometimes mislead us in determining the actual temperature of an object?
Answer:
The sense of touch can be influenced by previous experiences and surrounding temperatures, leading to inaccurate perceptions. For example, water that feels warm from an earthen pot may feel cooler from a tap, despite being at the same temperature.

Question 13.
What precautions should be taken when using a clinical thermometer?
Answer:
The thermometer should be cleaned with soap and water before and after use, and it should not be touched with fingers to avoid contamination. It should also be reset to ensure accuracy.

Long Answer Type Questions

Question 1.
Describe the differences between thermometers in terms of their use and range.
Answer:

Clinical Thermometers	Laboratory Thermometers
Clinical thermometers are designed specifically for measuring human body temperature.	Laboratory thermometers are used for a variety of scientific purposes.
They typically have a limited range, from around 35 °C to 42 °C, which is sufficient for detecting fevers and other health-related temperature variations.	Laboratory thermometers can measure a much wider range of temperatures, usually from-10 °C to 110 °C.
Clinical thermometers are used to take readings of body temperatures on Celsius or sometimes on Fahrenheit scale.	Laboratory thermometers are used to take readings of temperatures on Celsius scale or on Kelvin scale.
Clinical thermometers can be mercury thermometers, digital thermometers or non-contact infrared thermometers.	Laboratory thermometers use coloured alcohol or mercury as liquids that expand to show the temperatures readings.

Question 2.
Explain why digital clinical thermometers are preferred over earlier mercury thermometers.
Answer:
Mercury thermometers have mercury in their thin glass tubes inside. Mercury was used because of its shining and good expansion properties. But mercury is a highly toxic substance which is difficult to dispose of if the thermometer breaks.

Digital clinical thermometers are preferred over mercury thermometers because:

1. Digital thermometers do not use mercury. These use heat sensors to detect the body temperature.
2. The numbers on display on the digital thermometers are easier to read.

Question 3.
Explain the principle behind the Kelvin scale and its significance in scientific measurements.
Answer:
Scientifically there is no limit on the higher temperature that can exist. The highest temperature known is about 15 million degrees Celsius at the core of the Sui*. There can be more celestial objects having higher temperatures. The lowest temperature that can exist, till date known to the scientists, is close to -273 °C. On the Kelvin scale this lowest temperature of-273 °C is taken as 0 kelvin. 0 kelvin is also called absolute zero.

 

Question 4.
Describe the process and precautions necessary for using a laboratory thermometer.
Answer:
The thermometer should be handled carefully, avoiding any impact that could cause breakage. The bulb of the thermometer should be immersed in the liquid of which the temperature is being measured. The bulb of the thermometer should not touch the sides or bottom of the container.

The thermometer must be held vertically. The temperature should be read keeping the eye in line with the level liquid in the thermometer.The reading of the temperature must be taken immediately after the level of liquid in the column of the thermometer stops moving up. Temperature of the liquid may change if we hold on for long, before taking reading.After taking the reading while the thermometer is still immersed, it should be cleaned and stored properly to maintain its accuracy and longevity.

Question 5.
Describe how air temperature data is used in making weather forecasts.
Answer:
Air temperature data is an important component in weather forecasting as it influences atmospheric pressure, humidity, and wind patterns. Temperature data from various sources, including weather stations, satellites, and weather balloons is collected. This data is fed into computer models that analyse atmospheric conditions. Accurate temperature measurements allow forecasting of changes in weather, such as cold fronts, heatwaves, and rain. This information is very useful for agriculture, transportation, and public safety.

Question 6.
Name the three scales of measuring temperatures known to you. Write down the correct ways to write the names and units of these scales.
Answer:
The three scales of measuring temperature are the Celsius scale, the Fahrenheit scale and the Kelvin scale.

• The names of temperature scales Celsius scale, Fahrenheit scale and Kelvin scale, start with a capital letter.
• For the units for temperature, degree Celsius and degree Fahrenheit, the word degree starts with a lower-case letter while Celsius and Fahrenheit start with a capital letter.
• The unit kelvin starts with a lower-case letter.
• The symbols of all units (°C, °F, K) are capital letters. The degree sign (°) is not written with K.
• A full stop is not written after the symbol, except at the end of a sentence.
• While writing the temperature, a space is left between the number and the unit.
• For temperatures more than one degree, we use the plural of ‘degree’, that is, ‘degrees’, while writing the full form of the unit.

Question 7.
Explain the role of Anna Mani in the field of meteorology and her contributions to temperature measurement.
Answer:
Anna Mani was a great Indian scientist known as the Weather Woman of India. She made significant contributions to meteorology by developing and building a large number of weather measurement instruments. Her work reduced India’s reliance on foreign instruments. India has grown to lead the world in renewable energy due to the contributions of Anna Mani in this field.

Question 8.
Describe the process of measuring body temperature using a digital thermometer and explain why this method is preferred over traditional mercury thermometers.
Answer:
To measure body temperature using a digital thermometer, first, clean the tip with soap and water and reset the thermometer. Place it under the tongue, in the armpit, or rectally, as per instructions. Wait for the beep or visual indicator, then read the temperature displayed. Digital thermometers are preferred over mercury thermometers because they provide a digital readout, eliminating the risk of mercury exposure, are easier to read, and generally offer quicker and more accurate measurements.

Question 9.
Compare and contrast the uses of clinical and laboratory thermometers. Include their temperature ranges and applications in your discussion.
Answer:
Clinical thermometers are designed to measure human body temperature, typically ranging from 35º C-42º C. They are used for diagnosing fever or other temperature-related health issues. Laboratory thermometers, on theother hand, havea widertemperature range, from -10º C-110º C (for mercury thermometers) or -80º C-50º C (for alcohol thermometers). They are used in scientific experiments and industrial processes where precise temperature measurements are needed. The key difference lies in their design and application: clinical thermometers are suited for health-related use, while laboratory thermometers cater to scientific and technical needs.

 

Question 10.
Explain how the smallest value reading of a thermometer is determined and provide an example calculation.
Answer:
The smallest value reading of a thermometer is determined by the number of divisions between two major scale marks. For instance, if a thermometer has 50 divisions between 0º C and 100º C, each division represents a temperature increment of 2º C (calculated by dividing the total range, 100º C, by the number of divisions, 50). To calculate, if the thermometer has 10 divisions between 0º C and 10º C, then each division measures 1º C(10º C. divided by 10 divisions). This calculation helps ensure accurate temperature readings and is crucial for precise measurements in various applications.