Chapter-4 Heat

Explanation:

Cleaning the thermometer is very important to ensure the safety of other users. Infected thermometers can increase the spread of pathogens, resulting in illness. An Antiseptic solution should be preferred for cleaning the thermometer before and after it is used to avoid this. 

Explanation:

Conduction is transmitting heat energy from the hotter end to the colder end in solids. Because of collisions between neighbouring molecules or atoms, this conduction process occurs. Copper and Silver are considered to be good conductors of heat. 

Explanation:

A material which allows the transmission of energy in the form of heat within it without causing the movement of material is called the conductor of heat. It is exactly opposite to that of the insulators. Copper, iron, Silver etc., are considered to be good conductors of heat.

Explanation:

Clinical thermometer is a long and narrow glass tube which consists of a mercury bulb. It measures the temperature of the human body. 35°C to 42°C is the temperature range for this type of thermometer. The medical field has an effective use of clinical thermometers.

Explanation:

Due to the heat sources, the air nearby gets heated, and this causes them to rise. When they rise, some space is left; the air from the sides fills these empty spaces. Hence, heats get transferred into the air. This process of travelling heat in the air due to the movement of particles is called convection.

Explanation:

When there is any temperature difference between two bodies, a sensation with warmth in it flows. This form of energy is nothing but heat. Kinetic energy and mechanical energy are the types of heat energy. 

Explanation:

Different types of thermometers have different uses. The maximum-minimum thermometer measures the maximum-minimum temperature of the previous day, as mentioned in the weather report. This is also called a meteorological instrument. It is used in a greenhouse. 

Explanation:

The mercury does not fall or rise in a clinical thermometer when taken out because of the presence of a kink. This kink helps in preventing the backward movement of the mercury or coloured alcohol and also does not let them rise. 

Explanation:

High temperature cannot be measured by using clinical thermometers. This is because of its fixed range, 35°C to 42°C. This range is usually not enough to be classified as high temperatures. Hence, pyrometers are used to measure very high temperatures. 

Explanation:

Land breeze is a wind that blows from the land to the sea, occurring at night when the land cools down faster than the sea. The cooler, denser air over the land flows toward the warmer, less dense air over the sea, creating a breeze. It is usually weaker than the sea breeze and can have ecological effects in coastal areas.

Explanation:

The disposal of mercury when a thermometer breaks is a significant concern associated with its usage. Also, mercury is a toxic substance that harms human health. This is why much concern is associated with using mercury in thermometers. 

Explanation:

A long, narrow glass tube with a bulb at one end is called a clinical thermometer. Mercury is present in that bulb. A small shining thread of mercury is present outside the bulb. A fine bore is also attached to the bulb.

Explanation:

Dark colour absorbs heat while most of the heat gets reflected when there is light colour present and thus makes the thing inside cool. This is why people residing in hot climates are advised to paint their house walls with white colour as white colour reflects most of the sunlight.  

Explanation:

These days, hollow bricks are present. These hollow bricks can be used to fulfil the purpose of protecting buildings from heat and cold. When these hollow bricks are used to construct the house's outer walls, they will have trapped layers of air, thus protecting buildings from extreme heat or cool. 

Explanation:

Clinical thermometers are made in such a way that they can only measure human body temperature. The human body has a generally low-temperature range, so it doesn't go below 35°C or above 42°C. Hence, clinical temperature plays its role here. 

Explanation:

Clothes are bad conductors of heat, and hence, it prevents the transmission of heat from our body to the environment. That is why we are suggested to wear more layers of clothing during winter than just one thick piece.

Explanation:

The transfer of heat, which does not require any medium, is called radiation. The sun's heat reaches us through radiation as it cannot reach us through convection or conduction as there is no medium to do so. And both of these processes require a medium for their work which is not present. That is why radiation is used. 

Explanation:

Most heat is reflected by the light colour while dark colour absorbs heat. That is why we prefer light-coloured clothes in summer so that heat can transfer from our body to the environment and a sensation of coolness can be felt. In contrast, we prefer dark-coloured clothes so that heat can't go out in the environment from the body and can keep our body heated. 

Explanation:

The air over the land gets hotter and rises during the day as land gets heated faster than the sea. The space is then taken by the cooler air from the sea and the warm air which rises and moves towards the sea. This completes the cycle. The air that comes from the sea is called sea breeze. 

Explanation:

The heat gets trapped between the layers of the two blankets, and blankets being bad conductors of heat, resist the flow of heat from the body to the environment. Thus, the person wraps the blanket around his body and feels the warmth. This is why two thin blankets joined together are usually warmer than one thick blanket.

Explanation:

The flame heats the water near it, increasing the hot water. This results in the space above the flame, which is later filled by the side water. This site water gets heated and then rises again, resulting in more side water taking up the left space. This process continues till the whole water gets heated.

Explanation:

Similarities - Both are measured in celsius. Both are long and narrow tubes which have mercury filled inside the bulb.

Differences: Kink is present in clinical thermometer while absent in laboratory thermometer. Also, both have different ranges of measuring temperatures.

Explanation:

Precautions include:-

The thermometer should always be rinsed before use to avoid the spread of any pathogens. It should be handled with care so that breakage doesn't happen. The thermometer should not be held from the bulb side while taking the reading from it.

Explanation:

Precautions include:-

To avoid breaking the thermometer, one should handle it with care. When the thermometer is in substance, then only read the temperature. It should not be kept tilted. Instead, it should be kept upright. The thermometer should not have any movement while measuring the temperature.

Explanation:

The range of a laboratory thermometer is generally high, from –10°C to 110°C, while the average body temperature of the human body is 37°C. Also, kink is not present in laboratory thermometers, which can cause the fall of mercury, which can be dangerous. 

Explanation:

Light-coloured clothes are primarily preferred in summer. As most of the heat is reflected with white colour and hence can make the surface cool and eventually relaxed. Similarly, it can keep the human body relaxed in the scorching heat.

Cotton does the work well. Hence, we should wear light-coloured cotton clothes.

Explanation:

Black colour absorbs more heat falling on its surface than any other colour. That is why black bodies are good, or we can say better radiators, and due to this, the radiators in cars are painted black.

Explanation:

During the day, it is scorching in coastal areas. Windows of the houses should be faced towards the sea breeze so that sea breeze can come from the sea and can keep the house cool during the day time.

Explanation:

By our body temperature, the level of mercury increases from the actual reading. And hence mercury can come out and harm various things and humans. This is why it is advised not to hold the thermometer by its bulb while reading it.

Explanation:

Examples of conductors of heat include metals such as copper and aluminium, which can quickly transfer heat energy due to their high thermal conductivity. Examples of heat insulators include materials such as fibreglass and foam, which have low thermal conductivity and are used to insulate buildings and protect against heat transfer.

Explanation:

A mercury thermometer can be used to measure the temperature of boiling water, as it can measure high temperatures up to 357°C (675°F). This allows mercury thermometers to accurately measure the temperature of boiling water without the risk of the thermometer breaking or the liquid inside evaporating.

Explanation:

Dark-coloured clothes absorb heat better than light-coloured clothes because they have a higher absorption coefficient for visible and ultraviolet radiation. When sunlight or any other form of radiation falls on a dark surface, it gets absorbed and transformed into heat energy. In contrast, light-coloured clothes reflect most radiation, reducing their ability to absorb heat.