Earth Systems, Plates & Earth Materials — Chapter review · Science 6: Matter, Energy & Earth Systems, Grade 6
How can properties and indirect evidence reconstruct Earth’s processes? What formation histories are supported by a supplied rock packet, and where must identification remain uncertain?
Review the key ideas
Earth’s Spheres & System Interactions
Earth is usually described as four systems, but the division is a choice we make to keep track of things, not a set of walls that exist in the ground. Almost everything interesting happens where two of them meet and exchange matter and energy.
Inside Earth: Layers & Indirect Evidence
Nobody has ever been more than about 12 km into Earth, yet we know it has a liquid outer core and a solid inner one. Every bit of that knowledge is indirect, deduced from earthquake waves and from the planet's mass, and the reasoning is as worth learning as the answer.
Moving Plates, Boundaries & Earth Evidence
Earth's rigid outer shell is broken into about fifteen pieces that move a few centimetres a year, roughly the rate fingernails grow. Almost every earthquake, volcano and mountain range on the planet sits where two of those pieces meet.
Minerals: Properties, Patterns & Identification
A mineral's properties are not a list of coincidences; they come from how its atoms are arranged. That is why mica peels into sheets and halite breaks into cubes every time, and why a handful of simple tests can identify a specimen reliably when colour cannot.
Rocks, Weathering & the Rock Cycle
Rocks are not permanent; they are a stage in a cycle that has no fixed starting point and no required order. The size of the crystals in an igneous rock records how fast it cooled, and the difference between weathering and erosion is the difference between breaking and carrying.
Problem 1
Answer and explanation
25 + 20 + 5 + 10 = 60 mL, accounting for the stated arrival. Rain connects atmosphere and hydrosphere; infiltration connects water with geosphere; leaf interception involves biosphere. Later evaporation, drainage, or uptake is not quantified, so this is a short-interval record rather than a complete annual account.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 2
Answer and explanation
Not without adding relevant organisms, gases, energy, and processes. It may answer a narrower location question while omitting relationships needed for those changes.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 3
Answer and explanation
B preserves the accepted basic state distinction: mostly solid mantle, liquid outer core, solid inner core. Slow mantle flow does not imply a liquid ocean. Seismic patterns and other evidence help infer these states, while a simple cutaway cannot provide exact thickness or composition at every point. Lithosphere and crust also should not be confused.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 4
Answer and explanation
No. Pressure and composition as well as temperature affect state. The drawing should be evaluated through the relevant evidence, not a temperature-only rule.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 5
Answer and explanation
Separation grows by 6.0 cm in three years, a mean relative rate of 2.0 cm/year. Together with the ridge, this supports a divergent-boundary interpretation in the supplied model. It does not establish that each plate moves at exactly 2 cm/year or predict every earthquake or volcano.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 6
Answer and explanation
No. That is transform motion; outcomes depend on local conditions, and mountain building is not an automatic result of every boundary interaction.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 7
Answer and explanation
S matches R within the supplied three-candidate key. P differs in luster and Q in streak and scratch relation. The result combines defined properties rather than rely on surface color. It remains a match within this illustrative key, not a verified identification of an actual specimen or every possible mineral.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 8
Answer and explanation
No. Brittleness or toughness and resistance to scratching are different properties. Use the stated scratch record without equating it with ease of breaking.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 9
Answer and explanation
Cooling forms igneous rock; weathering supplies loose fragments; erosion transports them; deposition makes sediment layers; cementation can form sedimentary rock. The original igneous rock could instead undergo metamorphism while solid, or later remelt. The sequence does not require every rock to follow these events or specify their duration.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 10
Answer and explanation
Metamorphic rock under the stated process. If complete melting and later cooling were recorded instead, the formation account would follow an igneous pathway.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.