Scienc G8 Rev PSHS

In the context of scientific inquiry, which of the following best illustrates the principle of falsifiability?

• Accepting a theory simply because it aligns with common belief

• Relying solely on anecdotal evidence to support a claim

• Designing experiments that can potentially disprove a hypothesis

• Adopting a hypothesis without further testing

• Using historical data to confirm present trends

Answer explanation

Correct Answer: C

Explanation: Falsifiability is a cornerstone of the scientific method. It means that a hypothesis must be structured so that it can be tested and potentially disproven through experiments or observations. This approach ensures that scientific ideas are robust and subject to continual scrutiny.

Which process best explains the formation of distinct layers in Earth’s lithosphere?

• Accretion of cosmic dust over time

• Radioactive decay of surface elements

• Differentiation during Earth’s early molten state

• Weathering and erosion by atmospheric forces

• Impact events from meteor showers

Answer explanation

Correct Answer: C

Explanation: During Earth’s early history, the planet was largely molten. In this state, heavier elements sank toward the center while lighter elements rose to the surface, leading to the formation of distinct layers such as the core, mantle, and crust.

How do hydrologic processes contribute to the shaping of Earth’s surface features?

• By dissolving and transporting minerals across different regions

• By directly causing tectonic shifts

• By generating the Earth’s magnetic field

• By increasing the frequency of volcanic eruptions

• By blocking sunlight from reaching the surface

Answer explanation

Correct Answer: A

Explanation: The hydrosphere plays a critical role in landscape evolution. Water dissolves minerals and carries sediments from one location to another, which leads to erosion, sediment deposition, and the creation of various landforms.

Which of the following best explains the concept of feedback loops in Earth’s biosphere?

• A process where a change in a system leads to further changes that amplify or reduce the original effect

• A random occurrence without any measurable impact

• A one-time event that permanently alters an ecosystem

• A process that only affects isolated populations

• A series of events that are completely unrelated to previous conditions

Answer explanation

Correct Answer: A

Explanation: A feedback loop occurs when a change in a system produces effects that either reinforce (positive feedback) or diminish (negative feedback) the initial change. This concept is fundamental in understanding climate dynamics and ecosystem interactions.

Why is understanding atmospheric circulation important for predicting weather phenomena like typhoons?

• Because it solely determines tectonic activity

• Because it explains the movement and formation of storm systems

• Because it directly influences Earth’s orbit

• Because it solely drives volcanic eruptions

• Because it is unrelated to weather patterns

Answer explanation

Correct Answer: B

Explanation: Atmospheric circulation redistributes heat and moisture around the globe. This movement is crucial for the development and trajectory of storm systems, including typhoons, making it a key element in weather prediction.

Which aspect of volcanoes best demonstrates the interconnectedness of Earth’s internal processes?

• The color of the volcanic ash

• The seemingly random frequency of eruptions

• The role of tectonic plate movement in magma formation

• The occurrence of eruptions exclusively during daylight hours

• The existence of volcanoes only in isolated regions

Answer explanation

Correct Answer: C

Explanation: Volcanoes are closely linked to tectonic activity. The movement of tectonic plates causes stress and melting in the mantle, leading to magma formation and eventual volcanic eruptions. This process shows how internal geodynamic forces shape Earth’s surface.

What is the most significant factor influencing the propagation of seismic waves during an earthquake?

• The time of day when the earthquake occurs

• The type of rock and geological structures in the lithosphere

• The color and composition of surface minerals

• The presence of vegetation in the affected area

• The weather conditions at the time of the event

Answer explanation

Correct Answer: B

Explanation: Seismic waves travel at different speeds and directions depending on the physical properties of the materials they encounter. Variations in rock type, density, and the structure of geological layers greatly influence the behavior of these waves during an earthquake.

In studying natural disasters such as earthquakes, how does the scientific method improve our understanding and prediction capabilities?

• By allowing scientists to predict exact occurrences with no uncertainty

• By enabling systematic testing and revision of models based on observations and experiments

• By eliminating errors from scientific theories

• By completely preventing the occurrence of natural disasters

• By relying only on historical records without current data

Answer explanation

Correct Answer: B

Explanation: The scientific method involves observing phenomena, formulating hypotheses, conducting experiments, and refining models based on new evidence. This iterative process improves our understanding of earthquakes and helps develop models that can better forecast their behavior, even though absolute prediction remains challenging.

During a solar eclipse, why does the sky appear significantly darker even when the moon only partially covers the sun?

• Because the moon absorbs all the sunlight

• Because Earth’s atmosphere reflects all light away from the observer

• Because the direct sunlight is blocked, greatly reducing the overall light

• Because the eclipse triggers a sudden drop in Earth’s temperature

• Because the sun stops emitting light during the eclipse

Answer explanation

Correct Answer: C

Explanation: During a solar eclipse, the moon obstructs the direct sunlight, which is the primary source of brightness. Even if the sun isn’t completely covered, the significant reduction in direct light, combined with decreased atmospheric scattering, leads to a noticeably darker sky.

Which statement best reflects the interdisciplinary nature of Earth Science in understanding climate change?

• It relies solely on meteorological observations without considering geological history

• It integrates data from atmospheric, oceanic, biological, and geological studies

• It ignores chemical processes occurring in the environment

• It depends only on theoretical models with no empirical support

• It focuses exclusively on short-term weather patterns

Answer explanation

Correct Answer: B

Explanation: Earth Science is inherently interdisciplinary. Understanding climate change requires combining insights from various fields—meteorology, oceanography, biology, and geology—to capture the complex interactions within the Earth system. This comprehensive approach enables more accurate models and predictions.