Chapter 15: Temperature, Heat, And Expansion

When you touch a cold piece of ice with your finger, energy flows from your finger to the ice. This is because heat always flows from a warmer object to a colder object. The ice absorbs the heat energy from your finger, causing it to feel cold.

Ice tends to form first at the surface of bodies of water because of the unique properties of water. When the temperature drops, the surface of the water loses heat to the colder air, causing it to cool down. As water cools, it becomes denser and sinks, allowing warmer water from below to rise to the surface. This process continues until the entire body of water reaches the freezing point. At this point, the surface water, being the coldest, freezes first, forming a layer of ice on top.

Water expands when freezing because its molecules arrange themselves in a hexagonal structure, causing them to take up more space. As a result, the volume of water increases when it freezes, which can put pressure on the surrounding pipes. This increased pressure can cause the pipes to burst, leading to water leakage and damage.

When an iron ring is heated, the molecules within the ring gain energy and move faster, causing them to expand. This expansion leads to an increase in the size of the ring, including the hole. Therefore, the correct answer is that the hole becomes larger.

As a piece of metal cools, its molecules slow down and move closer together, causing the metal to contract or shrink. This contraction affects the entire piece of metal, including any holes or cavities within it. Therefore, the diameter of the hole in the metal decreases as it cools.

The fact that a thermometer "takes its own temperature" illustrates thermal equilibrium. Thermal equilibrium is the state in which two objects are at the same temperature and there is no net transfer of heat between them. When a thermometer is in thermal equilibrium with its surroundings, it means that the thermometer and the surroundings have reached the same temperature, indicating that there is no heat transfer occurring between them.

Aluminum has a higher specific heat capacity than copper, which means it requires more energy to raise its temperature compared to copper. Therefore, when equal masses of aluminum and copper wire are placed in a flame, copper will undergo a faster increase in temperature because it requires less energy to heat up.

If the specific heat of water were lower than it is, it would mean that water would require less energy to change its temperature. In the context of ponds in the cold of winter, this would mean that the water in the ponds would cool down faster and reach the freezing point more quickly. Therefore, if the specific heat of water were lower, ponds would be more likely to freeze.

The correct answer is that the energy per molecule is high, but little energy is transferred because of the few molecules in the spark. This means that while the individual molecules in the spark may have a high amount of energy, there are not enough molecules present to transfer a significant amount of energy to your skin. Therefore, the sparks do not harm you.

Desert sand being very hot in the day and very cold at night indicates that it has a low specific heat. Specific heat refers to the amount of heat required to raise the temperature of a substance. Since desert sand quickly heats up during the day and cools down rapidly at night, it means that it does not retain heat for long, indicating a low specific heat.

Iron normally warms up fastest when heat is applied because it has a higher thermal conductivity compared to the other materials listed. This means that heat can more easily and quickly transfer through iron, causing it to warm up faster. Water, glass, and wood have lower thermal conductivities, so they take longer to warm up when heat is applied.

A giant iceberg has a massive amount of internal energy due to its large size, while a hot cup of coffee has less internal energy because it is smaller. However, the hot cup of coffee has a higher temperature compared to the giant iceberg, as it is heated and meant to be consumed hot. Therefore, the correct answer is that the hot cup of coffee has a higher temperature, but less internal energy.

The Kelvin scale is an absolute temperature scale where 0 Kelvin represents absolute zero, the point at which all molecular motion ceases. The Celsius and Fahrenheit scales are relative scales based on the freezing and boiling points of water. Since the Kelvin scale is absolute, a temperature difference of 10 degrees Celsius is also equal to a temperature difference of 10 on the Kelvin scale. However, this is not the case for the Fahrenheit scale, as the size of the degree is different. Therefore, the correct answer is the Kelvin scale.

When two bodies at different temperatures are mixed together, they tend to reach a common temperature through the process of thermal equilibrium. In this case, pouring a liter of water at 40 degrees C into a liter of water at 20 degrees C will result in the final temperature being at or about 30 degrees C. This is because the warmer water will transfer some of its heat energy to the cooler water until both reach a balance, resulting in a final temperature that is intermediate between the initial temperatures.

The moderate temperatures of islands throughout the world can be attributed to water's high specific heat. Specific heat is the amount of heat energy required to raise the temperature of a substance. Water has a high specific heat, meaning it can absorb and retain a large amount of heat energy without a significant change in temperature. This property allows water to act as a temperature buffer, preventing extreme temperature fluctuations on islands.

When we enlarge a photograph of an iron ring, the image of the hole becomes larger. This is because enlarging a photograph means increasing its size, which includes all the elements within the photograph. Therefore, the image of the hole in the iron ring will also be enlarged, resulting in a larger image of the hole in the photograph.

A substance that heats up relatively quickly has a low specific heat because specific heat is a measure of how much heat energy is required to raise the temperature of a substance. If a substance has a low specific heat, it means that it requires less heat energy to increase its temperature, resulting in a quicker heating process.

Heat energy can be measured in both joules and calories. Joules are the standard unit of measurement for energy in the International System of Units (SI). Calories, on the other hand, are commonly used in nutrition and represent the amount of energy needed to raise the temperature of one gram of water by one degree Celsius. Therefore, both choices A (joules) and B (calories) are correct units for measuring heat energy.

The volume of water can change when it is warmed due to thermal expansion. However, the extent of the volume change depends on factors such as the initial temperature, the material of the container, and the amount of heating. In some cases, the volume change may be negligible, resulting in the same volume after being warmed by several Celsius degrees. Therefore, it is possible for a sample of water to sometimes have the same volume after being warmed.

Heat energy is a form of energy that flows from an object with a higher temperature to an object with a lower temperature. This is because heat tends to move from areas of higher energy (higher temperature) to areas of lower energy (lower temperature) in order to achieve thermal equilibrium. Therefore, the correct answer is that heat energy travels from an object with a high temperature to an object with a lower temperature.

Molecules that can absorb large amounts of energy in the form of internal vibrations and rotations have high specific heats. This means that they require a large amount of energy to increase their temperature. This is because the energy is being used to excite the internal vibrations and rotations of the molecules, rather than increasing their kinetic energy. Therefore, materials composed of such molecules will have high specific heats.

A red-dyed-water-in-glass thermometer would give ambiguous readings between 0 degrees Celsius and 8 degrees Celsius because this range is close to the freezing point of water. At these temperatures, the red dye may freeze or separate from the water, causing the readings to be unclear or inconsistent. Therefore, the thermometer would not provide accurate and reliable measurements within this temperature range.

When the metal ring is heated, the molecules in the ring gain energy and move faster. This increased motion causes the atoms in the ring to vibrate more vigorously, leading to an expansion in the size of the ring. As a result, the gap in the ring also becomes wider.

Water at 4 degrees Celsius expands when the temperature is lowered because it undergoes a unique phenomenon called the anomalous expansion of water. As water cools below 4 degrees Celsius, the hydrogen bonds between water molecules become more ordered, causing the molecules to move farther apart and the volume of water to increase. This is in contrast to most substances, including iron, wood, and helium, which contract and decrease in volume when the temperature is lowered. Therefore, water at 4 degrees Celsius is the only option that expands when the temperature is lowered.

Room temperature on the Kelvin scale is about 300 K. The Kelvin scale is an absolute temperature scale where 0 K represents absolute zero, the point at which all molecular motion ceases. Room temperature is typically defined as the average temperature experienced indoors, which is around 20-25 degrees Celsius or 68-77 degrees Fahrenheit. Converting this to Kelvin gives a range of approximately 293-298 K. Therefore, the closest option is 300 K.

When measuring a plot of land with a brass tape on a cold day, the tape will contract due to the cold temperature. This contraction will result in a shorter measurement than the actual size of the land. Therefore, the actual amount of land will be larger than what is measured.

When you stake out a plot of land with a steel tape on a very hot day, the heat causes the tape to expand. This expansion leads to an overestimation of the measured distance. As a result, the actual amount of land you will have will be smaller than what was initially measured.

Before ice can begin to form on a lake, the entire body of water must first cool down to 4°C. This is because water reaches its maximum density at this temperature, causing it to sink to the bottom. As the surface water continues to cool below 4°C, it becomes less dense and remains at the top, eventually reaching 0°C and freezing. This unique property of water allows lakes to freeze from the top down, while deeper layers remain liquid in winter.

Water has a unique property where it reaches its maximum density at 4 degrees Celsius. As it is heated from 4 degrees Celsius, the water molecules gain energy and move faster, causing them to spread out and occupy more space. This expansion leads to an increase in volume, causing the water to expand. On the other hand, when water at 4 degrees Celsius is cooled, the water molecules lose energy and slow down, causing them to come closer together and occupy less space. This contraction leads to a decrease in volume, causing the water to contract. Therefore, the correct answer is that water at 4 degrees Celsius expands when heated.

The correct answer is 4 degrees C. The question asks about the temperature at the bottom of Lake Tahoe, and the answer states that it is 4 degrees C.

Ice has a lower density than water because it is made of open-structured, hexagonal crystals. When water freezes, the water molecules arrange themselves in a specific pattern, forming a crystal lattice structure. This arrangement causes the molecules to be more spread out and less densely packed compared to the random arrangement of molecules in liquid water. As a result, the density of ice is lower than that of water, causing it to float in water.

When the temperature of water at 0 degrees Celsius is slightly increased, the water molecules gain energy and start moving faster. This increased kinetic energy causes the water molecules to spread out and occupy more space, resulting in an increase in volume. Therefore, the correct answer is "decreases" which contradicts the explanation provided.

When microscopic slush is added to water, it tends to decrease the water's density. This is because the slush particles occupy space within the water, causing the overall volume to increase without a proportional increase in mass. As a result, the mass per unit volume, which is the definition of density, decreases. Therefore, the presence of microscopic slush in water makes the water less dense.

When the temperature increases, glass expands more than mercury. This means that the volume of the glass in the thermometer increases more than the volume of the mercury. As a result, the column of mercury in the thermometer will be pushed down due to the expansion of the glass. Therefore, the column of mercury in a mercury thermometer will decrease when the temperature increases.

Helium expands the most when the temperature is increased compared to iron, wood, ice water, and equal volumes of other substances. This is because helium is a gas and its particles have more kinetic energy at higher temperatures, causing them to move faster and spread out, resulting in expansion. On the other hand, iron, wood, and ice water are solids or liquids, and their particles are closely packed, so they expand less when heated. Therefore, helium exhibits the greatest expansion when the temperature is increased.

Helium is a gas at room temperature and it exhibits the most significant contraction when the temperature is decreased. This is because gases have more freedom of movement compared to solids or liquids, and as the temperature decreases, the gas molecules slow down and move closer together, resulting in contraction. Iron, wood, and water are solids or liquids, and although they may also contract to some extent with temperature decrease, their contraction is not as pronounced as that of helium. Therefore, helium contracts the most when the temperature is decreased.

When the temperature is increased, most substances expand or increase in volume due to the increase in kinetic energy of their particles. However, ice water is an exception to this general trend. When ice water is heated, the temperature of the water rises until it reaches the boiling point of water, at which point it starts to boil and convert into steam. During this phase change, the water molecules gain enough energy to break the intermolecular bonds that hold them together in a rigid structure, causing the water to expand and occupy a larger volume. Therefore, ice water contracts when the temperature is increased.

When a kilogram block of iron at 40 degrees C is placed into a kilogram of water at 20 degrees C, heat will transfer from the iron to the water until they reach thermal equilibrium. Since the iron is at a higher temperature than the water, heat will flow from the iron to the water, causing the temperature of the iron to decrease and the temperature of the water to increase. However, the specific heat capacity of iron is lower than that of water, meaning that a given amount of heat will cause a greater change in temperature for iron compared to water. Therefore, when the two substances reach thermal equilibrium, the final temperature will be less than 30 degrees C.

When the bimetallic bar made of copper and iron strips is heated, the copper strip expands more than the iron strip. This is because different materials have different coefficients of thermal expansion, which determine how much they expand or contract when heated or cooled. In this case, copper has a higher coefficient of thermal expansion than iron, causing it to expand more when heated. As a result, the bar bends toward the iron strip, as the copper strip expands more and exerts a greater force.

When a closed, sealed can of air is placed on a hot stove, the air inside the can undergoes an increase in temperature due to the heat from the stove. This increase in temperature leads to an increase in pressure as the air molecules gain more energy and move faster, colliding with the walls of the can more frequently and with greater force. However, there is no change in the mass of the air inside the can, as mass is a measure of the amount of matter and remains constant unless there is a change in the composition of the air. Therefore, the correct answer is "temperature" and "pressure".

When ice floats in water, it displaces a volume of water equal to its own volume. This is because the density of ice is lower than that of water. The reason for this is the presence of a vast number of open spaces in the hexagonal ice crystals. These open spaces create gaps between the ice molecules, making ice less dense than water. As a result, when ice is placed in water, it floats and a part of it extends above the surface, with the volume of the extended part being equal to the volume of water displaced.

When the temperature of ice is decreased, it causes the water molecules to slow down and come closer together. This results in a decrease in the volume of the ice. Therefore, as the temperature decreases, the volume of the ice decreases.