Inside Earth: Layers & Indirect Evidence — Practice · Grade 6 Science

Chapter: Earth Systems, Plates & Earth Materials

What this practice covers

By the end of Inside Earth: Layers & Indirect Evidence you should be able to:

8 questions, written answer and multiple choice, each with a worked explanation.

Vocabulary used: lithosphere, indirect evidence, evidence, system boundary, uncertainty.

Problem 1

Why should crust and lithosphere not be interchangeable?
Answer and explanation

Lithosphere includes crust plus rigid uppermost mantle. The categories use different criteria and boundaries.

Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.

Problem 2

Is the whole mantle liquid because it moves?
Answer and explanation

No. Most is solid; slow deformation and local melting are different descriptions.

Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.

Problem 3

Does one absent S-wave arrival uniquely map every layer?
Answer and explanation

No. It is evidence to interpret with geometry, multiple stations, and other records rather than a complete map by itself.

Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.

Problem 4

Can a readable cutaway be used for precise layer fractions?
Answer and explanation

Only if it is explicitly to scale. Otherwise it illustrates order and relationships rather than exact dimensions.

Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.

Problem 5

Develop a complete response: Select the better supported basic model and explain two evidence or classification limits. Include relevant evidence and one method or model limit.
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 6

Apply the unit independently: A drawing places a solid inner core inside a liquid outer core. Is that impossible because the center is hotter? Give a reason and a relevant qualification.
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 7

Which statement correctly uses lithosphere in Inside Earth: Layers & Indirect Evidence?
  1. The entire mantle is a liquid ocean.
  2. lithosphere: The rigid outer layer including the crust and uppermost mantle.
  3. The crust and the whole lithosphere are identical layers.
  4. One illustrative result establishes every real condition and needs no further evidence.
Answer and explanation

lithosphere: The rigid outer layer including the crust and uppermost mantle.

The rigid outer layer including the crust and uppermost mantle. 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.

Problem 8

Which statement correctly uses indirect evidence in Inside Earth: Layers & Indirect Evidence?
  1. The crust and the whole lithosphere are identical layers.
  2. The entire mantle is a liquid ocean.
  3. indirect evidence: Observations used to infer a feature that is not directly inspected.
  4. One illustrative result establishes every real condition and needs no further evidence.
Answer and explanation

indirect evidence: Observations used to infer a feature that is not directly inspected.

Observations used to infer a feature that is not directly inspected. 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.

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