Advanced Geophysical Science Final Exam Study Guide

Foundational Concepts of Physics and Work

Within the study of geophysics, understanding the mechanics of work and energy is fundamental. Work is defined as the application of force over a distance; therefore, an example of work not being done is a ball sitting idle on a field. Even if forces are present, without displacement in the direction of the force, work equals zero.

Potential energy is characterized as conserved or stored energy, representing the energy an object has due to its position or state. In a practical scenario, such as an arrow in a bow, the system contains potential energy based on the tension of the bowstring. When an arrow is held in a bow before it is shot, it possesses $80\,J$ of potential energy. According to the transcript, the kinetic energy at this specific point is noted as $224$ , although typically kinetic energy represents the energy of motion.

Power and energy are closely related but distinct concepts. A $200\text{-watt}$ light bulb is documented to have more power and energy than a $100\text{-watt}$ light bulb. In this context, power is the rate at which work is done or energy is transformed.

Forces and Newton’s Laws of Motion

Forces are a cornerstone of geophysical science. Four primary truths regarding forces include that they are defined as a push or a pull, they are represented as vectors (possessing both magnitude and direction), and they have the capacity to change the state of an object’s motion. Inertia is defined as an object’s resistance to force or a change in its state of motion.

Newton’s First Law of Motion is known as the Law of Inertia, stating that an object at rest stays at rest and an object in motion stays in motion unless acted upon by an unbalanced force. Newton’s Second Law of Motion defines the relationship between mass, force, and acceleration with the formula $F = m \times a$ . This is often referred to as the Law of Acceleration.

As a practical application of the Second Law, if a golf ball with a mass of $10\,kg$ has a force of $80.3\,N$ applied to it, the resulting acceleration is calculated as $8.03\,m/s^2$ . When multiple forces are acting on an object, if the forces pulling and pushing are even (balanced), the net overall force is $0$ .

Atomic Structure and Chemical Bonding

An atom's identity and behavior are determined by its subatomic particles: protons and neutrons (making up the nucleus) and electrons. The atomic number of an atom is exactly equal to the number of protons it contains. Neutrons are located in the nucleus and carry a charge of $0$ . A subatomic particle is composed of protons and neutrons.

For the element Oxygen, the atomic structure consists of $8$ protons, $8$ neutrons, and $8$ electrons. The number of valence electrons, which are those in the outermost shell, is determined by the group number on the periodic table; Oxygen has $6$ valence electrons. Atoms can carry an electrical charge depending on the movement of electrons: an atom achieves a negative charge when it gains electrons and a positive charge when it loses electrons.

Bonding occurs in two primary forms. Covalent bonding occurs when atoms share a pair of electrons, typically between a non-metal and another non-metal. Ionic bonding occurs when there is a transfer of electrons, usually between a metal and a non-metal. Molecular structures can be represented using Lewis Dot Diagrams; for Oxygen, this involves the symbol O surrounded by dots representing its $6$ valence electrons, and for Magnesium ( $Mg$ ), the symbol is shown with $2$ dots ( $Mg:$ ).

Metric System and Kinematics

The International System of Units (SI) is used for all scientific measurements. The SI unit for mass is the kilogram ( $kg$ ). The metric conversion chart follows a hierarchy: Kilo, Hecto, Deca, Base (Meter, Liter, Gram), Deci, Centi, and Milli. Under this system, $100,000\,meters$ is equivalent to $100\,kilometers$ . Furthermore, $100\,grams$ is equivalent to $100,000\,milligrams$ . In common notation, "mm" stands for millimeter and "m" stands for meter.

Kinematics units are specific: acceleration is measured in $m/s^2$ , and velocity is measured in $m/s$ . Kinetic energy ( $KE$ ) is calculated using the formula $KE = \frac{1}{2} m v^2$ . For a rollercoaster car with a mass of $100\,kg$ moving at $20\,m/s$ south from a hill that is $20\,km$ high, the kinetic energy is $20,000\,joules$ . Momentum is determined by two factors: mass and velocity ( $M \times V$ ). Impulse is defined as the change in momentum.

Chemistry, pH, and States of Matter

The pH scale is a measure of acidity or basicity, ranging from $0$ to $14$ . Substances with a pH from $0$ to $6$ are considered acids, a pH of $7$ is neutral, and a pH from $8$ to $14$ constitutes a base. An example of a chemical property is found in antacid tablets, which act as a buffer to maintain a $pH$ level near $7$ .

Changes in matter are categorized as either physical or chemical. A physical change, such as melting, involves a change in state without altering the chemical composition. A chemical change, such as digestion, results in the formation of new chemical substances.

Matter exists in several states, including liquids and gases. A similarity between the two is that they are both considered fluids. A primary difference is that gases do not have a definite volume, whereas liquids do.

Waves and the Electromagnetic Spectrum

Waves are disturbances that transfer energy. A wavelength is the distance between consecutive corresponding points of a wave. In sound waves, the volume is determined by amplitude: a quiet sound is characterized by a low amplitude, while a louder sound is characterized by a high amplitude.

The electromagnetic (EM) scale ranks radiation from low frequency to high frequency as follows: Radio waves, Microwaves, Infrared, Visible light, Ultraviolet ( $UV$ ), X-rays, and Gamma rays. Gamma rays are the most dangerous to humans, while radio waves are the least dangerous. When a light ray strikes a mirror, it experiences reflection, where the light bounces off at the same angle it arrived.

Electricity and Magnetism

Electricity involves the movement of charges. There are two types of electric charges: positive and negative. Electric forces depend on two main factors: the distance between charges and the amount of charge present. The subatomic particle responsible for an electric current is the electron. In magnetism, it is noted that magnets do not necessarily have to be touching each other to exert a force; therefore, the statement that they must touch is False.

Earth Science and the Environment

The hydrosphere encompasses all the water on Earth. On a global scale, the ocean's tides are caused primarily by the gravitational pull of the moon. Geological changes occur through weathering, the breakdown of rock, and erosion, the process of rock being worn away. Mechanical weathering does not change the chemical composition of the rock.

Environmental science focuses on the carbon cycle and human influence. Greenhouse emissions are gases that trap heat in the atmosphere. Human impacts on the carbon cycle and the natural world include deforestation, industrial agriculture, and the burning of fossil fuels. An ecological footprint is defined as the amount of land needed to sustain a specific population. One method to reduce a carbon footprint is to drive less. Additionally, wind turbines serve the purpose of generating renewable energy, though their ideal placement and the broader definitions of biodiversity and cladograms are essential topics for further study.

Lab Safety and Scientific Method

Laboratory safety is paramount in geophysical science. Correct safety procedures include "wafting" to smell chemicals rather than inhaling directly. Prohibited actions include drinking chemicals. If a student is struggling with instructions, the recommended action is to review the material with their group.

The scientific method is a systematic approach to problem-solving. The steps must be followed in a specific order:

Problem (Defining the question)
Background Research (Establishing a baseline)
Hypothesis (Writing a testable "If… then" statement)
Procedure/Experiment (Controlling variables)
Observation/Analyze Data (Organizing data into charts or graphs)
Conclusion (Explaining if the hypothesis is correct)

Data visualization is essential for analyzing results. This includes the use of line graphs (often plotting velocity versus time) and pie charts to understand proportional data distribution.