Earth and Water
Which part of the Earth’s structure is responsible for creating the planet's magnetic field?
The outer core, due to the movement of liquid iron and nickel.
Why do planes often fly in the lower stratosphere rather than the troposphere?
To avoid the weather disturbances (clouds, storms) that are mostly confined to the troposphere.
What is the point on the Earth's surface directly above where an earthquake starts?
The epicentre.
What is the most common cause of a tsunami?
An underwater earthquake (or seaquake) that displaces a large volume of water.
How does the "greenhouse effect" differ from "global warming"?
The greenhouse effect is a natural process that keeps Earth warm; global warming is the human-induced intensification of this effect.
Is the mantle a liquid or a solid? Explain its behavior.
It is a solid, but it behaves plastically, meaning it can flow very slowly due to extreme heat and pressure.
Describe the chemical composition and the physical state of the mantle. Why is it said to "flow under pressure"?
Solid silicate rock that behaves plastically (ductile). It "flows" because of high temperatures and pressure, causing convection currents that move tectonic plates.
Which volcanic eruption style is characterized by a gentle flow of fluid lava?
Effusive eruption.
What is "drawdown" in the context of a tsunami?
It is the rapid retreat of sea water from the shore, exposing the seabed before the first wave arrives.
In what way does the melting of polar ice create a "positive feedback loop"?
Melting ice reduces the Earth's albedo (reflectivity); the darker ocean absorbs more heat, which in turn causes more ice to melt.
What happens to "surface runoff" if the ground is made of impermeable concrete?
The amount of runoff increases because the water cannot undergo infiltration into the soil.
What do the initials "CFCs" stand for, and why are they harmful?
They stand for Chlorofluorocarbons; they are harmful because they release chlorine atoms that destroy ozone molecules.
How is a "caldera" formed?
It is formed when a volcano's summit collapses into a partially emptied magma chamber following a massive eruption.
Why do tsunami waves increase in height as they approach the coast?
As the water becomes shallower, the wave slows down and its energy is compressed, forcing the wave height to increase (a process called shoaling).
Can we still define events like "extreme floods" as purely "natural" disasters?
While the mechanism is natural, their increased frequency and intensity are often linked to human-induced climate change, making them "anthropogenic" in scale.
How does the physical state of the inner core differ from the outer core?
The inner core is solid due to immense pressure, whereas the outer core is liquid (molten) metal.
Explain the chemical process of ozone (O3) formation.
UV radiation splits an oxygen molecule (O2) into two atoms, which then react with other O2 molecules to form O3.
Compare the Richter scale and the Mercalli scale.
The Richter scale measures the magnitude (energy released), while the Mercalli scale measures the intensity (observed effects and damage).
Define a "storm surge" and its cause.
A storm surge is an abnormal rise of water generated by a storm (like a hurricane), over and above the predicted astronomical tide.
Evaluate the impact of urban "heat islands" during a heat wave.
Urban areas with lots of concrete and little vegetation trap more heat, making temperatures significantly higher than in surrounding rural areas.
How do the crust and the topmost mantle relate to the lithosphere?
They are the two components that make up the lithosphere, forming the rigid outer shell of the Earth.
Why was the Montreal Protocol a significant international achievement?
It was the first global treaty to successfully phase out the production of ozone-depleting substances.
Define the terms "foreshock" and "aftershock" and their relationship to a "mainshock."
Foreshocks are smaller quakes before the mainshock; aftershocks follow the mainshock as the crust adjusts.
Why are high-humidity heat waves more dangerous to humans than dry heat waves?
High humidity prevents the evaporation of sweat, which is the body's primary mechanism for cooling down.
Why is a "binding" agreement like the Paris Agreement more complex to implement than a voluntary one?
Binding agreements require legal accountability, monitoring systems, and often face political resistance regarding national sovereignty and economic costs.