Physics Past Paper - Temperature and its Measurement PDF

Grade 6 Subject Name Physics Chapter Name Temperature and its Measurement Chapter Owner (SME) Parmeshwar singh Creation Date 2/01/2025 Faculty Reviewer FR Date dd/mm/yy SME 2 Reviewer (name) SME2R date dd/mm/yy Language Reviewer (name)s LR Date dd/mm/yy Final Correction Date dd...

Grade 6 Subject Name Physics Chapter Name Temperature and its Measurement Chapter Owner (SME) Parmeshwar singh Creation Date 2/01/2025 Faculty Reviewer FR Date dd/mm/yy SME 2 Reviewer (name) SME2R date dd/mm/yy Language Reviewer (name)s LR Date dd/mm/yy Final Correction Date dd/mm/yy **7. Temperature and its Measurement** 7.1 HOT OR COLD? ================ In our daily lives, the feeling of hot and cold is something we experience all the time. It affects what we wear, what we eat, and even how we stay comfortable in different seasons. We come across objects that feel either hot or cold, like a cup of steaming tea or a scoop of ice cream. During winter, the chilly air often makes us feel cold, while in summer, the warmth of the sun can feel hot. Our sense of touch helps us decide if something is hot or cold. \(a) Hot (b) Cold Fig. 7.1 Hot and Cold ### Activity to understand hot and cold **Preparation**: Label three containers A, B, and C. Fill A with cold water, B with hot water, and C with a mix of both.  Fig. 7.2 Understanding hot and cold through an activity **Experiment**: Submerge left hand in A (cold water) and right hand in B (hot water) for 2-3 minutes. Then, place both hands simultaneously in C. **Output** - Container A (Cold Water): Left hand feels cold due to cold water. - Container B (Hot Water): Right hand feels hot due to hot water. - Container C (Mixed Water): The hand previously in cold water may feel warmer, while the hand previously in hot water may feel colder. This is due to the temperature contrast between the two hands, causing a perception shift in the mixed water\'s temperature. 7.1.1 Temperature ----------------- Temperature helps us understand how hot or cold something is. It\'s not just a feeling but something we can measure. We use a special tool called a **thermometer** to measure temperature. Fig. 7.3 Thermometer 7.2 MEASUREMENT OF TEMPERATURE ============================== - The temperature is generally measured in **degrees Celsius**. It is denoted as [ ^∘^*C*]{.math.inline}. - There is another unit of temperature i.e. **degree Fahrenheit**, which is denoted as [ ^∘^*F*]{.math.inline}.\ The S.I. unit of temperature is **kelvin** (K). - The normal temperature of the human body is 37 °C. Note that the temperature is stated with its unit. 7.2.1 Clinical thermometer -------------------------- You may have seen a thermometer, which is used to measure body temperature. This type of thermometer is known as a clinical thermometer. Modern versions of these thermometers display temperatures digitally and are often referred to as digital clinical thermometers. They operate on batteries and measure temperature when placed in contact with a person\'s body. Clinical thermometers typically use the Celsius scale for measuring temperature. On this scale, the unit of temperature is degree Celsius, written as °C.  Fig. 7.4 A digital clinical thermometer ### How to Use a Clinical Thermometer - Wash your hands and clean the tip of the digital 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 thermometer to beep or flash a light to indicate it\'s done. - Remove the thermometer from the mouth and read the temperature displayed digitally. - Record the temperature. - Clean the tip of the thermometer again with soap and water, then dry it. ### Precautions - Read the instruction manual of the thermometer before use. - Wash the tip of the thermometer with soap and water before and after each use. - While washing, ensure the digital portion (such as the display) does not get wet. - Do not hold the thermometer by the tip. The normal body temperature is usually around 37.0 °C, but it can be a little higher or lower for different people. Things like age, time of day, and activity can affect body temperature. You can check your temperature at different times and write down the readings. After a month, see if there are any changes and try to figure out why. Body temperature usually stays between 35 °C and 42 °C. For small children or older people, the thermometer can be placed in the armpit, but it will show a temperature that is 0.5 °C to 1 °C lower than the actual body temperature. **Note**: clinical thermometers are designed specifically for measuring body temperature, and following these precautions helps ensure their effectiveness and longevity. 7.2.2 Laboratory thermometer ---------------------------- A laboratory thermometer is used to measure temperatures in science experiments and laboratories. It looks like a long, narrow glass tube that is sealed at one end. The thermometer has a bulb at one end, filled with liquid, usually alcohol (coloured red for visibility) or mercury. This liquid moves up or down inside the tube as the temperature changes. The thermometer also has a **Celsius scale** marked on the tube, showing temperatures in degrees Celsius (°C). To find the temperature, you look at the mark where the top of the liquid column aligns with the scale. Fig. 7.5 Laboratory thermometer ### Range of a Laboratory Thermometer Laboratory thermometers can measure temperatures in a specific range. For example, above thermometer has a range from -10 °C to 110 °C. This means it can measure temperatures as low as -10 °C and as high as 110 °C. ### Smallest Measurement on a Laboratory Thermometer **The smallest value a thermometer can measure depends on the distance between the marks on its scale.**  Fig. 7.6 Smallest Measurement on a Laboratory Thermometer **For example, in the thermometer shown above** - **The difference between two bigger marks is 10 °C.** - **There are 10 smaller divisions between these marks.** - **Each small division measures 1 °C.** **So, the smallest temperature this thermometer can measure is 1 °C.** ### Correct Way to Use a Laboratory Thermometer **To measure temperature accurately, follow these steps:** - **Hold the thermometer vertically and ensure it is not tilted.** - **Immerse the bulb in the liquid or object you are measuring, but make sure the bulb does not touch the bottom or sides of the container (e.g., beaker).** - **Read the temperature while the thermometer is still immersed.** - **Look straight at the liquid column to avoid errors. Your eye should be at the same level as the top of the liquid column.** ### Precautions - Avoid exposing the laboratory thermometer to direct sunlight or flames as it may break. - Keep the thermometer upright without tilting it. - Ensure that the bulb of the thermometer is surrounded by the substance whose temperature is being measured. - It\'s important that the bulb does not touch the surface of the container. 7.2.3 Advantages of using mercury as a thermometric liquid ---------------------------------------------------------- Mercury is used as a thermometric liquid because of the following advantages: 1. It does not stick to the glass, therefore readings are more accurate. 2. It is an opaque and shiny liquid and hence it is easily visible through the glass. 3. Its expansion is uniform at all temperatures. 4. It has a **low freezing point** [(**−39** ^**∘**^**C**)]{.math.inline} **and a high boiling point** [(**357** ^**∘**^**C**)]{.math.inline}**.** Therefore, it can be used over a wide range of temperatures. 5. It is easily available in pure state. 6. It is a non-volatile liquid and hence vapors are not formed in the empty part of the thermometric tube. 7.2.4 Air temperature --------------------- You may have noticed thermometers, like the one shown in Fig. 7.5, hanging on the walls of your school laboratory, a doctor\'s clinic, or hospitals. These devices help give an approximate measurement of the room\'s temperature. Have you ever seen weather updates in newspapers, TV news, or on the internet? These reports often include the highest and lowest temperatures of the day, giving us an idea of the weather. 7.3 TEMPERATURE SCALE ===================== Temperature scales help us measure how hot or cold something is. The three main temperature scales are: ### Celsius (°C) - Water freezes at **0 °C** and boils at **100 °C**. - Commonly used worldwide, including in India. ### Fahrenheit (°F) - Water freezes at **32 °F** and boils at **212 °F**. - Mostly used in the USA. ### Kelvin (K) - Starts at **absolute zero**, the coldest possible temperature. - Water freezes at **273 K** and boils at **373 K**. - Often used in science. Each scale is used in different places or for specific purposes, but they all help us understand temperature better. QUICK REVIEW ============ Hot and cold are sensations experienced daily, influenced by objects and weather. Hands in cold, hot, and mixed water demonstrate how temperature differences affect perception. Temperature measures how hot or cold something is, determined using a thermometer. Common temperature units are degrees Celsius (°C), Fahrenheit (°F), and Kelvin (K). Normal human body temperature is approximately 37°C. To read a thermometer, observe the scale and divisions, and clean it before use. Laboratory thermometers measure temperatures in experiments, usually from -10°C to 110°C, with each division often representing 1°C. Mercury is ideal for thermometers because it is visible, non-sticky, expands uniformly, and works over a wide temperature range. Wall thermometers provide room temperature, and weather reports share daily high and low temperatures. Temperature scales: - Celsius: Water freezes at 0°C and boils at 100°C. - Fahrenheit: Water freezes at 32°F and boils at 212°F. - Kelvin: Starts at absolute zero, with water freezing at 273 K and boiling at 373 K. WORKSHEET 1 =========== **MULTIPLE CHOICE QUESTIONS WITH SINGLE CORRECT ANSWER** I. Hot or Cold -------------- 1. Which of the following is an example of something cold? 2. During winter, why do we feel cold? 3. In the activity to understand hot and cold, how does the hand in hot water feel when placed in mixed water? 4. What helps us decide if an object is hot or cold? 5. What happens when one hand is placed in hot water and the other in cold water, and then both are placed in mixed water? II. Temperature Measurement --------------------------- 1. What does a thermometer measure? 2. The unit of temperature in the SI system is: 3. Which thermometer is used for measuring human body temperature? 4. Why should a clinical thermometer not be used to measure the temperature of objects? 5. What is the range of a laboratory thermometer? III. Temperature Scales ----------------------- 1. Water freezes at what temperature on the Celsius scale? 2. What is the freezing point of water on the Kelvin scale? 3. The boiling point of water on the Fahrenheit scale is: 4. Which temperature scale is commonly used in India? 5. Which of the following is the absolute zero point on the Kelvin scale? WORKSHEET 2 =========== **MULTIPLE CHOICE QUESTIONS WITH SINGLE CORRECT ANSWER** 1. What is the normal body temperature in Celsius? 2. Which of the following liquids is commonly used in laboratory thermometers? 3. What is the purpose of the kink in a clinical thermometer? 4. Which thermometer uses batteries to function? 5. What should be the position of your eye while reading a thermometer? 6. How do you ensure that a clinical thermometer is clean before use? 7. Which of the following is true about a laboratory thermometer? 8. Why is mercury used in thermometers? 9. What is the freezing point of water on the Fahrenheit scale? 10. How do you correctly use a laboratory thermometer to measure temperature? 11. Which thermometer has a scale ranging from -10°C to 110°C? 12. How does the digital thermometer work? 13. What is the purpose of the mercury in thermometers? 14. The boiling point of water in Kelvin is: 15. Which of the following temperatures is equal to 32°F? 16. **Assertion (A):** Mercury is used in thermometers because it is shiny and easily visible. 17. **Assertion (A):** Laboratory thermometers are used to measure body temperature. 18. **Assertion (A):** The Kelvin scale does not have negative values.