Clouds, Matter, and Physical Science Concepts

Cirrus clouds are characterized by their thin, wispy appearance, resembling feathers. They form at high altitudes, typically above 20,000 feet, where temperatures are very low. Composed mainly of ice crystals, these clouds indicate fair weather but can also signal that a change in the weather may be approaching. Their delicate structure and high altitude distinguish them from other cloud types, making "cirrus" the correct answer for this question.

Cumulonimbus clouds are towering, dense clouds that form in unstable atmospheric conditions, typically associated with severe weather. They are capable of producing heavy precipitation, thunderstorms, and lightning due to the intense updrafts and moisture they contain. These clouds can also generate strong winds and even tornadoes, making them a key indicator of severe weather events. Their vertical development and associated characteristics distinguish them from other cloud types, linking them directly to intense weather phenomena.

Sublimation is the process in which a solid transitions directly into a gas without passing through the liquid state. This occurs when the solid gains enough energy, typically through heat, to overcome the intermolecular forces holding its particles together. A common example of sublimation is dry ice (solid carbon dioxide) turning into carbon dioxide gas. This process is significant in various applications, including freeze-drying and the preservation of certain materials.

When water reaches its boiling point of 100°C at standard atmospheric pressure, it undergoes a phase change from liquid to gas. The large bubbles that form during this process are composed of water vapour, also known as steam. This steam is generated as the liquid water molecules gain enough energy to break free from the liquid state, resulting in the formation of gas bubbles that rise to the surface. Thus, the bubbles are filled with water vapour.

Surface tension occurs due to the cohesive forces between water molecules, which are attracted to each other through hydrogen bonding. At the surface of the water, molecules experience a net inward force because they are surrounded by other water molecules on the sides and below, but not above. This imbalance creates a "film" effect on the surface, allowing it to resist external forces. Thus, cohesion plays a crucial role in establishing surface tension, making the statement true.

To find the density of the cube, first calculate its volume by multiplying the length, width, and height: \(5 \, \text{cm} \times 2 \, \text{cm} \times 4 \, \text{cm} = 40 \, \text{cm}^3\). Next, use the density formula, which is mass divided by volume: \( \text{Density} = \frac{\text{mass}}{\text{volume}} = \frac{160 \, \text{g}}{40 \, \text{cm}^3} = 4 \, \text{g/cm}^3\). Thus, the density of the cube is 4 g/cm³.

Cohesion refers to the attractive forces between water molecules, allowing them to stick together, which is evident in phenomena like surface tension. Adhesion, on the other hand, describes the attraction between water molecules and different materials, enabling water to cling to surfaces such as glass or paper. The first two statements accurately capture these definitions, while the other statements misrepresent the concepts, as cohesion does not cause water to climb up a paper towel, and adhesion does not lead to the formation of round water droplets.