Chapter: 07. Forms Of Matter Solids, Liquids And Gases
Explain the characteristics of the three different forms of matter: solids, liquids, and gases.
Solids possess a fixed shape and size because their particles are tightly packed and vibrate in fixed positions, preventing them from flowing. Liquids, however, have a fixed volume but no fixed shape, readily taking the form of their container due to particles that are close but can move past one another, allowing them to flow easily. Gases lack both a fixed shape and volume, expanding to fill any container entirely because their particles are far apart and move freely, making them easily flow and often invisible.
Describe an activity to demonstrate that a liquid can flow and takes the shape of its container, including the materials and observations.
To demonstrate this, one can gather various containers such as a bottle, a glass, a bowl, and a shallow plate, along with some water. First, pour water from the bottle into the glass, observing how the water takes the cylindrical shape of the glass. Next, pour the water from the glass into the bowl, noting that it now conforms to the bowl’s rounded shape. Finally, pouring the water onto the shallow plate will show it spreading out to match the plate’s flat form. This clearly illustrates that water, as a liquid, flows easily and continuously adapts its shape to fit whatever container it occupies.
Explain the concept demonstrated by Manvi’s balloon experiment and Mihika’s incense stick observation.
Manvi’s balloon experiment, where a pricked balloon caused a stick to tilt, demonstrates that air, despite being a gas and largely invisible, possesses mass. The inflated balloon contained air, contributing to its weight, and when the air escaped, that side became lighter, revealing air’s tangible property. Mihika’s observation of incense stick smell spreading throughout a room highlights a key characteristic of gases: they spread out to fill all available space. The scent particles, in gaseous form, diffused from the corner to permeate the entire room, illustrating that gases do not have a fixed shape or confined space but readily expand to occupy their surroundings.
Discuss why sand is considered a solid, even though it exhibits behaviors similar to liquids when poured.
While sand can be poured and appears to take the shape of its container, much like a liquid, it is fundamentally classified as a solid. This is because each individual grain of sand maintains its own fixed shape and size. Unlike liquid molecules that can freely move past each other and change the overall substance’s form, sand’s individual particles are rigid. The apparent flow and shape-taking behavior arise from the collective movement of countless tiny, independent solid particles, rather than the substance itself having no fixed shape. This characteristic distinguishes it from true liquids, which lack individual fixed forms.