Science Grade 10

Pangaea

A supercontinent that existed millions of years ago, derived from Greek words meaning "all Earth."

Panthalassa

A super ocean surrounding Pangaea, meaning "all seas."

Tectonic plates

Massive, irregular slabs of solid rocks that envelop the Earth's surface.

Contraction theory

Suggested that Earth's surface contracted and wrinkled as it cooled after formation, leading to mountain ranges.

Continental Drift Theory

Proposed by Alfred Wegener, explaining the movement of continents over time.

Seafloor Spreading Theory

Proposed by Harry Hess, stating that ocean floors move and carry continents.

Mantle Convection Theory

Heat transfer process in the mantle causing tectonic plate movement.

Slab Pull Theory

States that gravity and plates themselves cause plate movements through subduction.

Plate Boundaries

Regions where tectonic plates interact, leading to various geological phenomena.

Divergent Plate Boundary

Where plates move apart, creating rifts or rift valleys.

Convergent Plate Boundary

Where plates collide, forming subduction zones or mountain ranges.

Transform Plate Boundary

Where plates slide past each other, causing earthquakes.

Paleontological Evidence

Fossils supporting the movement of continents over time.

Evidence from Glaciation

Glacial deposits indicating past continental positions.

Evidence from structure and rock type

Geological features suggesting past connections between continents.

Layers of the Earth

Crust, mantle, and core, each with distinct characteristics and compositions.

Atmosphere

Gaseous envelope surrounding the Earth, composed of different layers with varying temperatures.

Biosphere

Sphere encompassing all life forms on Earth, from microscopic organisms to large organisms.

Topography

The study of the current terrain features of a region and the graphic representation of a particular landform on a map

Landforms

Natural physical features on the surface of Earth influenced by water, wind, ice, and tectonic plates

Aeolian Landforms

Landforms formed by the chemical and mechanical action of the wind, such as dunes, loess, and mushroom rocks

Depositional Aeolian Landforms

Types include Erg, Ripples, Barchan, Longitudinal Dunes, Transverse Dunes, and Star Dunes

Erosional Landforms

Created from exclusively erosional and weathering activities, examples include Mesas, Buttes, and Canyons

Mountainous and Glacial Landforms

Landforms exhibiting slopes, summit areas, and local relief, including Volcanoes, Hills, and Valleys

Volcano

A cone-shaped hill or mountain formed by the extrusion of lava or ejection of rock fragments from a vent

Geomorphology

The study of the relief features of Earth’s crust, with Volcano as an example of extrusive volcanism

Plate Tectonics

Scientific study of the origin and arrangement of the broad structural features of Earth’s surface

Earthquake

Natural phenomenon characterized by a sudden, violent shifting of massive plates underneath Earth’s surface

Excessive exposure to visible light

Prolonged exposure to visible light, especially in the blue region, can lead to eye damage.

Lasers and blindness

Lasers have the potential to cause blindness due to their intense light.

Ultraviolet rays and skin damage

Overexposure to UV rays can result in skin burns, tanning, and even skin cancer.

Damage to the retina

Ultraviolet rays have the ability to harm the retina, affecting vision.

Greenhouse effect

Gases in the Earth's atmosphere trap the Sun's heat, leading to global warming.

Enhanced greenhouse effect

Increased greenhouse gases from human activities intensify the greenhouse effect, contributing to global warming.

Reflection

The bouncing off of light from an object, following the law of reflection.

Mirrors

Plane and spherical mirrors reflect light, forming real or virtual images based on their shape.

Refraction

The bending of light as it passes from one medium to another, enabling the use of lenses and prisms.

Refractive Index

Describes how fast light travels through a material, calculated as the speed of light in a vacuum divided by the speed of light in the medium.

Node of Ranvier

Gaps or nodes in the myelin sheath

Central Nervous System (CNS)

Command center of the body, processes information, and sends instructions

Cerebrum

Largest part of the brain, shapes attitudes, emotions, and personality

Cerebellum

Coordinates muscle actions and balance

Brain Stem

Connects spinal cord to the brain, controls survival functions

Spinal Cord

Organ of neurons and blood vessels, carries impulses to the brain

Peripheral Nervous System

Links CNS to the body, made of nerves

Autonomic Nervous System (ANS)

Controls smooth muscles, cardiac muscles, and glands

Endocrine System

Glands that secrete hormones, control body functions

Hormones

Chemical messengers that regulate body processes

Pituitary Gland

"Master gland" producing hormones controlling other glands

Thyroid Gland

Regulates heart rate, blood pressure, and metabolism

Adrenals

Located above kidneys, produce adrenaline in stress

Pancreas

Produces insulin and glucagon to control blood sugar

Diabetes

Chronic condition affecting energy conversion in the body

Hypothyroidism

Thyroid produces insufficient hormones

Hyperthyroidism

Thyroid produces excess hormones

Encephalitis

Infection and inflammation of the brain

Parkinson’s Disease

Progressive nervous system disorder affecting movement

Alzheimer’s Disease

Condition causing severe mental deterioration

DNA

Hereditary material, double-stranded helical molecule

Watson-Crick DNA Model

Describes DNA as a double helix, based on x-ray diffraction

Rosalind Franklin

British physicist who contributed to the DNA double helix discovery

Nitrogenous Bases

Flat structures inside the helix, with adenine pairing with thymine and guanine pairing with cytosine using hydrogen bonds.

Base Complementarity

Adenine pairs with thymine using two hydrogen bonds, while guanine pairs with cytosine using three hydrogen bonds.

DNA Structure

Contains 10 bases every 360° turn, with bases 3.4 angstrom units apart and a double-helix diameter of 20 angstroms.

Semiconservative Replication

DNA replication mode where each new DNA molecule contains one original strand and one newly synthesized strand.

Griffith's Transformation Experiment

Study by Frederick Griffith on bacterial strains (R and S strains) causing pneumonia, leading to the discovery of DNA as the genetic material.

Genetic Mutations

Changes in genes or chromosomes affecting an organism's phenotype, including examples like Albinism, Sickle Cell Anemia, and Down Syndrome.

Chromosomal Aberrations

Inheritable changes in chromosomes, including deletions, duplications, inversions, and translocations.

Genetic Disorders

Include Tay-Sachs Disease, Phenylketonuria, Cri-du-chat Syndrome, Duchenne Muscular Dystrophy, among others.

Theory of Plate Tectonics

Earth's lithosphere movement explained by the contraction theory, continental drift theory, and seafloor spreading theory.

Mechanism of Plate Movements

Explained by the Mantle Convection Theory and Slab Pull Theory, involving heat transfer, gravity, and subduction processes.

Divergent Plate Boundary

Landmass above this boundary is torn apart into distinct pieces, creating an ocean as surrounding waters fill the space.

Convergent Plate Boundary

Two plates move toward each other, forming a subduction zone or an orogenic belt.

Orogenic Belt

A region of deformed rocks formed when two plates collide.

Oceanic-oceanic Convergence

When two oceanic plates collide, a subduction zone is created.

Oceanic-continental Convergence

Oceanic plate subducts beneath the continental plate, leading to rock melting and magma formation.

Continental-continental Convergence

When two continental plates collide, they suture together, forming mountain ranges.

Transform Plate Boundary

Plates slide against each other in opposite directions, causing earthquakes but no mountain or volcano formation.

Earthquakes

Shaking of Earth due to tectonic plate movements, with different types like dip slip, faults, and seismic waves.

Hypocenter

The point beneath the surface where an earthquake originates.

Epicenter

The point directly above the earthquake's focus on the Earth's surface.

Snell's Law

Describes the relationship between the angles of incidence and refraction when light passes through different media using the equation n1 sinθ1 = n2 sinθ2.

Refraction of Light

The bending of light rays as they pass from one medium to another due to a change in speed.

Shallowing Effect

Phenomenon where objects submerged in a liquid appear shallower than they actually are due to refraction at the liquid's surface.

Endocrine System

A system of glands that produce and secrete hormones to regulate various bodily functions and processes.

Hormones

Chemical messengers that instruct cells to alter their activities, controlling processes like metabolism, growth, mood, and sexual function.

Homeostasis

The body's ability to maintain internal stability by adjusting to external conditions, crucial for survival.

Pituitary Gland

Often referred to as the "master gland," it produces hormones that regulate activities of other endocrine glands.

Genetic Manipulation

Involves techniques like hybridization and recombinant DNA to transfer genes between organisms for desired traits.

Evolution

Refers to changes in the genetic composition of populations over time, with theories like Lamarck's inheritance of acquired characteristics and Darwin's natural selection.

Gene Flow

Movement of genes between populations due to migration, influencing genetic diversity.

Genetic Drift

Changes in allele frequencies in a population due to random sampling, including effects like the bottleneck effect and founder effect.