Temperature and its Measurement
Fill in the Blanks:
1. The normal body temperature of a healthy human being is approximately _______.
- Answer: 37°C
2. The device used to measure temperature is called a _______.
- Answer: thermometer
3. A clinical thermometer is used to measure the temperature of the _______.
- Answer: human body
4. The unit of temperature on the Celsius scale is _______.
- Answer: degree Celsius (°C)
5. A laboratory thermometer typically has a range from _______ to _______.
- Answer: -10°C, 110°C
6. The Fahrenheit scale measures the normal body temperature as _______.
- Answer: 98.6°F
7. The SI unit of temperature is _______.
- Answer: kelvin (K)
8. _______ thermometers are safer to use because they do not contain mercury.
- Answer: Digital
9. The liquid inside a laboratory thermometer is often _______ or _______.
- Answer: alcohol, mercury
10. Absolute zero, the lowest possible temperature, is _______ in Celsius.
- Answer: -273.15°C
True or False:
1. Mercury thermometers are still widely used because mercury is safe to handle.
- Answer: False (Mercury is toxic and digital thermometers are safer)
2. The Celsius scale is more commonly used than the Fahrenheit scale in scientific studies.
- Answer: True
3. A clinical thermometer can measure temperatures ranging from -10°C to 110°C.
- Answer: False (A clinical thermometer measures body temperature, typically 35°C to 42°C)
4. Absolute zero is the highest temperature that can be measured.
- Answer: False (Absolute zero is the lowest temperature, at -273.15°C or 0 K)
5. Digital thermometers are easier to read than mercury thermometers.
- Answer: True
6. A laboratory thermometer is suitable for measuring the temperature of boiling water.
- Answer: True
7. The Kelvin scale uses the degree symbol (°) to denote temperature.
- Answer: False (The Kelvin scale does not use the degree symbol)
8. The temperature of a body tells us how hot or cold it is.
- Answer: True
9. A clinical thermometer is used for measuring the temperature of liquids.
- Answer: False (It is used for measuring human body temperature)
10. The temperature of boiling water remains constant while it is boiling.
- Answer: True
Question / Answers
1. What is temperature and why is it important?
Answer: Temperature is a measure of how hot or cold an object is. It is important because it helps us understand the heat levels of bodies or substances, which is crucial in various daily activities, health monitoring, and scientific experiments.
2. Why is our sense of touch not reliable for measuring temperature?
Answer: Our sense of touch can be misleading because it depends on the previous temperature our body experienced. For example, water that feels warm to one hand may feel cool to the other after it has been in ice water.
3. What is a clinical thermometer? How is it different from a laboratory thermometer?
Answer:
A clinical thermometer is used to measure human body temperature, with a typical range of 35°C to 42°C. It is often digital and easy to read.
A laboratory thermometer is used for measuring a broader range of temperatures, usually from -10°C to 110°C. It is used in experiments, not for measuring body temperature.
4. What is the normal body temperature of a healthy human being?
Answer: The normal body temperature of a healthy human is approximately 37.0°C or 98.6°F.
5. Name the three main temperature scales and explain their differences.
Answer:
Celsius Scale (°C): Used worldwide in most scientific measurements.
Fahrenheit Scale (°F): Used in some countries like the United States.
Kelvin Scale (K): Used in scientific work, particularly in physics. Kelvin does not use a degree symbol (°), and the zero point (0 K) represents absolute zero, the coldest possible temperature.
6. How do you use a digital clinical thermometer to measure body temperature?
Answer:
- Wash the tip of the thermometer with soap and water.
- Reset the thermometer by pressing the reset button.
- Place the thermometer under the tongue and close your mouth.
- Wait for the beep or flash signal.
- Read the temperature and clean the thermometer again after use.
7. What precautions should you take while using a laboratory thermometer?
Answer:
Handle it carefully to avoid breakage.
Do not hold it by the bulb.
Read the temperature while the thermometer is still in the substance.
Keep it vertical during measurement.
8. What is the range of a laboratory thermometer, and why can’t it be used to measure body temperature?
Answer: The range of a laboratory thermometer is typically -10°C to 110°C. It cannot be used for measuring body temperature because its range is too broad and not sensitive enough for the small temperature changes in the human body.
9. How does a thermometer work to measure temperature?
Answer: A thermometer contains a liquid (such as mercury or alcohol) that expands when heated and contracts when cooled. The level of the liquid rises or falls in the narrow tube, indicating the temperature on a marked scale.
10. Why is it important to clean a thermometer before and after use?
Answer: Cleaning the thermometer before and after use ensures hygiene, preventing the spread of infections, especially when it is used to measure body temperature.
11. Why is mercury being replaced by digital thermometers?
Answer: Mercury is toxic and poses a health risk if the thermometer breaks. Digital thermometers are safer, easier to read, and do not involve toxic substances.
12. What are the key differences between Celsius and Fahrenheit scales?
Answer:
The Celsius scale measures temperature in degrees Celsius (°C), where water freezes at 0°C and boils at 100°C.
The Fahrenheit scale measures temperature in degrees Fahrenheit (°F), where water freezes at 32°F and boils at 212°F.
13. How can we convert temperatures from Celsius to Kelvin?
Answer: To convert a temperature from Celsius to Kelvin, use the formula:
Temperature in Kelvin = Temperature in Celsius + 273.15
14. What is absolute zero, and what temperature is it on the Kelvin scale?
Answer: Absolute zero is the lowest temperature possible, where all molecular motion stops. On the Kelvin scale, absolute zero is 0 K, which is equivalent to -273.15°C.
15. What precautions should you take while reading a thermometer to ensure accuracy?
Answer:
- Ensure the thermometer is not touching the sides of the container if measuring liquids.
- Hold the thermometer vertically.
- Read the thermometer at eye level for an accurate reading.
16. What role does temperature play in weather reports?
Answer: Temperature is a key factor in weather reports, indicating how hot or cold the environment is. Daily maximum and minimum temperatures help predict weather conditions, such as heat waves or cold fronts.
17. What happens to the liquid in a thermometer when it is exposed to higher temperatures?
Answer: When a thermometer is exposed to higher temperatures, the liquid (mercury or alcohol) inside expands, causing the level of the liquid to rise in the tube, which indicates a higher temperature reading.
18. Why do we measure air temperature and how is it important for weather forecasting?
Answer: Air temperature is measured to understand current weather conditions and to predict future weather patterns. It is essential for weather forecasting, agriculture, and daily life activities like dressing appropriately for the weather.
19. How does temperature influence human health?
Answer: Body temperature is a critical indicator of health. A rise in body temperature (fever) can indicate an infection or illness, while too low a body temperature (hypothermia) can be life-threatening.
20. What is the smallest temperature change that a laboratory thermometer can measure?
Answer: The smallest temperature change a laboratory thermometer can measure depends on its scale. For example, a thermometer with 10 divisions between 0°C and 10°C can measure a minimum change of 1°C per division.
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