Year 9 Science Semester 1 Exam Revision Flashcards

Vocabulary flashcards for key concepts in the Year 9 Science Semester 1 Exam Revision Guide.

Plate Tectonics

Theory explaining how major landforms are created due to subterranean movements

Tectonic Plates

The sections of the planet that make up the crust

Seafloor Spreading

Movement of tectonic plates apart that allows lava from the mantle to slip through and form new crust

Earthquake

A collision of tectonic plates, transform or convergent

Richter Scale

A scale used to determine the magnitude of earthquakes.

Volcano

An opening in the Earth's crust where molten lava, ash, and gases are ejected.

Atom

The basic unit of a chemical element, consisting of protons, neutrons, and electrons.

Subatomic Particles

Particles that make up an atom, including protons, neutrons, and electrons.

Mass Number

The total number of protons and neutrons in an atom's nucleus.

Nuclide Symbols

Symbols used to identify specific atoms and their number of protons and neutrons.

Periodic Table

A table that organizes elements by increasing atomic number into groups and periods.

Ions

Atoms that have gained or lost electrons, resulting in an overall electrical charge.

Ionic Compounds

Compounds formed from the electrostatic attraction between cations and anions.

Isotopes

Atoms of the same element with the same atomic number but different numbers of neutrons.

Radioactive Decay

The process by which unstable atomic nuclei lose energy by emitting radiation.

Sympathetic Nervous System

Part of the nervous system that prepares the body for 'fight or flight' response.

Earth's Layers

The structure of the Earth, including the crust, mantle, outer core, and inner core.

Continental Drift

The theory that continents have moved over geological time to their current locations.

Convergent Boundaries

Tectonic plate boundaries where plates move towards each other.

Divergent Boundaries

Tectonic plate boundaries where plates move apart from each other.

Transform Boundaries

Tectonic plate boundaries where plates slide past each other.

Chemical Formulas

Notations that represent the composition of chemical compounds.

Valency Rules

Guidelines used to determine how atoms combine to form compounds.

Reaction Time

The time taken to respond to a stimulus, often measured in experiments.

Alpha decay

A type of radioactive decay where an atom emits an alpha particle.

Beta decay

A type of radioactive decay where an atom emits a beta particle.

Gamma decay

A type of radioactive decay where an atom emits gamma radiation.

Half-life

The time required for half of the radioactive atoms in a sample to decay.

Stress

A state of mental or emotional strain resulting from adverse or demanding circumstances.

Acute stress

A type of stress that is short-term and often arises from specific events.

Chronic stress

A type of stress that is long-term and persists over an extended period.

Distress

A negative form of stress that can lead to anxiety and other health issues.

Eustress

A positive form of stress that can motivate and energize individuals.

Internal stressors

Stressors that originate from within an individual, such as thoughts and feelings.

External stressors

Stressors that come from outside an individual, such as environmental factors.

Central nervous system

The part of the nervous system that consists of the brain and spinal cord.

Peripheral nervous system

The part of the nervous system that consists of all the nerves outside the central nervous system.

Neuron

The main components of a neuron that play a role in neural communication.

Neurotransmitters

Chemical messengers that transmit signals across a synapse from one neuron to another.

Lock-and-key process

The mechanism by which neurotransmitters bind to receptors on the postsynaptic neuron.

Voluntary responses

Responses that involve conscious control and are mediated by specific divisions of the nervous system.

Fight-flight-freeze response

An automatic physiological reaction to an event that is perceived as stressful or frightening.

Spinal reflex

An involuntary and nearly instantaneous movement in response to a stimulus.

Adaptive responses

Responses that help an organism to survive and adapt to changes in the environment.

Continental Drift Theory

The theory proposed by Alfred Wegener that continents were once joined together in one giant land mass called Pangea.

Fossil evidence

Fossils of the same species found on separate continents, suggesting they were once joined.

Rock evidence

Identical rocks of the same age and type found on separate continents.

Glacier evidence

Grooves and rock deposits left by ancient glaciers found on different continents.

Mid-Ocean Ridge

Two oceanic plates spreading apart creates this geological feature.

Rift Valley

Two continental plates spreading apart creates this geological feature.

Earthquake Cause

Pressure build-up over time leads to the plates slipping, causing this geological event.

Continental Crust

Thicker parts of the crust that make up the earth's continents.

Oceanic Crust

Thinner parts of the crust that sit under the oceans; more dense than continental crust.

Ocean-to-Continent Collision

Denser oceanic plate pushed underneath the continental plate, creating mountains, volcanoes, and ocean trenches.

Continent-to-Continent Collision

Crumpling occurs due to the similar densities of the continental plates, creating mountain ranges.

Ocean-to-Ocean Collision

Older, denser crust will subduct below the newer crust, creating deep ocean trenches and undersea volcanoes.

Sea-Floor Spreading

Hot magma from the earth's mantle pushing up through the crust at the bottom of the ocean, creating a divergent plate boundary.

Convection Currents

The rising and falling of mantle creates these, moving the earth's crust like items on a conveyor belt.

Ring of Fire

The string of volcanoes and increased earthquake activity that exists around the edges of the Pacific Ocean, along the edge of the Pacific plate.

Focus of Earthquake

The point at which the earthquake begins.

Epicentre of Earthquake

Directly above the point below the surface where the movement in the crust began; generally experiences the largest vibrations on the surface.

Compression

When a force is applied to a rock and, if this is done slowly enough, will result in the folding of rocks.

Anticlines

Folds that bend upwards, forming an 'A' shape.

Synclines

Folds that bend downwards.

Fault

If the Earth breaks, rather than bends, it produces this.

Body Waves

Waves that radiate outward and travel through the interior of the Earth.

Surface Waves

Waves that tend to travel only along the Earth's surface.

P-waves

Cause reverse faults; the fastest of the seismic waves that can travel through all of the Earth's interior layers.

S-waves

Travel in the form of transverse waves (up-and-down motion); slower than P-waves and cannot travel through fluids.

Love Waves

Transverse waves that move in a side-to-side motion, like a snake.

Rayleigh Waves

Move with a rolling motion like an ocean wave.

Atomic Number

The number of protons in an atom's nucleus, which makes it unique.

Protons

Exist in the nucleus of an atom and have a positive charge (+).

Neutrons

Exist in the nucleus of an atom and have no charge (are neutral).

Electrons

Exist around the nucleus and have a negative charge (-).

Cations

Ions with a positive charge.

Anions

Ions with a negative charge.

Electron Shells

Paths on which electrons orbit the nucleus.

Groups

Vertical columns on the periodic table where elements have the same number of valence electrons.

Periods

Horizontal rows on the periodic table where elements have the same number of electron shells.

Valence Electrons

Electrons that are in an atom's outermost shell.

Stable Isotope

An isotope with a stable nucleus where protons and neutrons are held together strongly.

Unstable Isotope

An isotope with an unstable nucleus where protons and neutrons are not held together strongly.

Nuclear Decay

The process by which the nuclei of unstable isotopes undergo change to become more stable.

Radioisotopes

Another term for unstable isotopes.

Sea floor spreading

Movement of two lithospheric plates causing the depth of the sea to increase.

Structure of an atom

A nucleus containing neutrons and protons, surrounded by fast moving electrons.

Layers of the Earth

Inner core, outer core, mantle and crust.

Alfred Wegener

The German scientist who theorized that all continents were once one big continent called Pangea.

Asthenosphere

A semi-fluid layer of the mantle where convection currents are located.

Radioactive isotopes

Isotopes that decay over time, contributing to the heat energy of the Earth's core.

Radiocarbon dating

A method used by scientists to estimate the age of fossils based on remaining Carbon-14.