Comprehensive Science Review: Plate Tectonics, Geologic Time, EM Spectrum, and Physics

Flashcard set containing 60 vocabulary terms covering plate boundaries, the geologic time scale, electromagnetic waves, and Newton's laws of motion.

Plates

Rigid sections of the lithosphere that move as a unit.

Subduction

The process in which one tectonic plate is forced beneath another into the mantle.

Trench

A deep depression in the seafloor formed at a subduction zone.

Mid-ocean ridge

A continuous underwater mountain range formed where tectonic plates move apart.

Volcanic island arc

A chain of volcanoes that forms parallel to a trench, usually at a subduction zone.

Divergent Boundary

A plate boundary formed when two tectonic plates move apart from each other, creating tension, forming new crust, mid-ocean ridges, and rift valleys.

Reykjanes Ridge

The section of the Mid-Atlantic Ridge that includes Iceland and spreads apart at rates of 2 to 5 cm per year.

Convergent Boundary

A plate boundary formed when two tectonic plates move towards each other, where crust is destroyed and volcanoes, mountains, or trenches form.

The Himalayas

The highest and one of the youngest mountain ranges in the world, stretching for about 2,400 kilometers (1,500 miles) across Asia.

Transform Boundary

A plate boundary formed when two tectonic plates slide past each other horizontally without creating or destroying crust, causing earthquakes.

San Andreas Fault

An example of a transform boundary where the Pacific Plate and North American Plate slide past each other.

Rift Valley

A feature formed at a divergent boundary that can also be found at the bottom of the ocean where seafloor spreading occurs.

Geologic Time Scale

A system used by scientists to organize Earth's 4.6-billion-year history into hierarchical divisions based on major geological and biological changes.

Eon

The largest division of geologic time, spanning hundreds of millions to billions of years.

Era

A subdivision of an eon that divides time blocks based on major changes in Earth's fossil record.

Period

A subdivision of an era characterized by specific rock layers and evolutionary milestones.

Epoch

A smaller subdivision of a period that allows scientists to describe Earth's history in greater detail.

Hadean Eon

The eon representing the formation of Earth and its earliest conditions.

Archean Eon

The eon characterized by early life and ancient crust.

Proterozoic Eon

The eon during which oxygen increased and complex life developed.

Phanerozoic Eon

The eon characterized by abundant visible fossil life, containing the Paleozoic, Mesozoic, and Cenozoic eras.

Mesozoic Era

The era known as the age of reptiles and dinosaurs, comprising the Triassic, Jurassic, and Cretaceous periods.

Cenozoic Era

The era known as the age of mammals, during which humans appear very late.

Paleocene Epoch

An epoch lasting from about 56 to 33.9 million years ago, representing the first epoch of the Cenozoic Era after the extinction of non-avian dinosaurs.

Eocene Epoch

A warm epoch from about 56 to 33.9 million years ago when mammals rapidly diversified and early ancestors of modern mammals evolved.

Oligocene Epoch

A cooler and drier epoch from about 33.9 to 23 million years ago when forests declined, open habitats expanded, and modern mammal groups evolved.

Miocene Epoch

An epoch from about 23 to 5.33 million years ago when grasslands expanded, mammals diversified, and early human relatives began to appear.

Pliocene Epoch

A cooler and drier epoch from about 5.33 to 2.58 million years ago when grasslands expanded and early human relatives diversified.

Pleistocene Epoch

An epoch from about 2.58 million years ago to 11,700 years ago, often called the Ice Age due to repeated cycles of glacial and interglacial periods.

Holocene Epoch

The current geological epoch that began about 11,700 years ago following the Pleistocene Ice Age, characterized by a warmer climate.

Electromagnetic Wave

A wave made of oscillating electric and magnetic fields that travels through space at approximately $3 \times 10^8\,\text{m/s}$ without needing a material medium.

Electric Field

The region around an electric charge where another electric charge experiences a force.

Magnetic Field

The region around a magnet or a moving electric charge where magnetic forces act.

Transverse Wave

A wave that moves the medium perpendicular to the direction of wave motion.

Longitudinal Wave

A wave that moves the medium parallel to the direction of wave motion.

Crest

The highest point of a wave.

Trough

The lowest point of a wave.

Amplitude

The height of a wave that indicates its strength and energy content.

Wavelength

The distance between two consecutive crests or troughs of a wave.

Frequency

The number of complete wave cycles or vibrations passing a fixed point in one second, expressed in Hertz.

Electromagnetic Spectrum

The range of all electromagnetic waves classified according to their frequency from low frequency to high frequency.

Radio Waves

Electromagnetic waves discovered by Heinrich Hertz that have long wavelengths and low frequencies, used for broadcasting music, news, and navigation.

Microwaves

Electromagnetic waves discovered by James Maxwell with frequencies ranging from $300\,\text{MHz}$ to $300\,\text{GHz}$.

Infrared Radiation

Electromagnetic radiation discovered by Frederick Herschel, often referred to as heat radiation because it is felt as warmth.

Visible Light

The region of the electromagnetic spectrum that allows human vision, ranging from red (longest wavelength, lowest energy) to violet (shortest wavelength, highest energy).

Ultraviolet Radiation

Electromagnetic radiation discovered accidentally by Johann Ritter, originating mainly from the sun and capable of causing sunburns.

X-Rays

Electromagnetic radiation discovered accidentally by Wilhelm Roentgen, used in medical imaging to view bones and organs.

Gamma Rays

Electromagnetic radiation discovered by Paul Ulrich Villard with frequencies higher than $3 \times 10^{19}\,\text{Hz}$, having the shortest wavelength and highest energy.

Newton's Second Law of Motion

States that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass ($F = ma$).

Newton's Third Law of Motion

Also known as the Law of Interaction, which states that every action has an equal and opposite reaction.

Normal Force

The support force exerted by a surface that pushes an object upward or perpendicular to the surface.

Gravity

A force directed downward toward Earth with symbol $F_g$, calculated using the formula $F_g = mg$.

Friction

The force that opposes the motion of two surfaces in contact with each other.

Tension Force

The pulling force transmitted through a rope, string, cable, or chain when stretched by forces acting at its ends.

Force

A push or pull acting on an object that can change its state of motion, speed, direction, shape, or size.

Balanced Forces

Forces acting on an object that are equal in size and opposite in direction, resulting in a net force of zero.

Unbalanced Forces

Forces acting on an object that are not equal in size or not opposite in direction, resulting in a non-zero net force that changes motion.

Newton's First Law of Motion

States that an object will remain at rest or continue moving at a constant velocity in a straight line unless acted upon by a net external force.

Inertia

The tendency of an object to resist changes in its state of motion.

Mass

The measure of the amount of matter in an object and a quantitative measure of its inertia, with the SI unit of kilogram ($\text{kg}$).