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Abrasion :  The mechanical wearing away of a rock by friction, rubbing, scraping, or grinding.
Abyssal : Pertaining to the great depths of the oceans, generally 1000 fathoms (2000 meters) or more below sea level.
Acceleration : is the increase of velocity in unit time
Acid : a type of chemical that produces hydrogen ions when dissolved in water and turns blue litmus red.
Adhesive force : the force that exists between unlike molecules
Aftershock : An earthquake that follows a larger earthquake. Generally, many aftershocks occur over a period of days or even months after a major earthquake.
Amylase : a chemical in saliva that breaks down starch
Anode : the negative terminal in a battery; the positive electrode in an electrolytic cell
Anti-oxidant : a substance that inhibits oxidation
Archimedes Priniciple : when a body is wholly or partly submerged in a fluid the up thrust equals the weight of the fluid displaced (i.e. pushed aside).
Arid : A dry climate such as a desert.
Artesian water : Groundwater confined in an aquifer and under pressure great enough to cause the water to rise above the top of the aquifer when it is tapped by a well.

Arteries : blood vessels that carry oxygen-rich blood from the heart throughout the body
Ash : Volcanic fragments the size of dust particles.
Assimilation : The process by which hot magma incorporates or dissolves the surrounding solid country rock.
Asteroid : A small, rocky planetary body orbiting the Sun. Asteroids are numbered in the tens of thousands. Most are located between the orbit of Mars and the orbit of Jupiter. Their diameters range downward from 1000 km.
Asthenospherethe: portion of the earth’s mantle that is below the lithosphere
Atom : The smallest unit of an element. Atoms are composed of protons, neutrons, and electrons.
Atomic Number : of an atom is the number of protons in the nucleus. Also known as the proton number and represented by the letter Z


Base : a type of chemical that produces hyroxide ions and turns red litmus blue
Beam: is a stream of light and is shown by a number of rays; it may be parallel, diverging (spreading out) or converging (getting narrower).
Bolus : the food ball prepared in the mouth and swallowed
Bonds : forces that link atoms, group of atoms, or molecules together
Boyle’s Law : the volume of a fixed mass of gas is inversely proportional to the pressure, if the temperature is unchanged.
Buoyant Force : is the upward force that acts on a body in a liquid whether the body is floating or submerged (and this force makes the object seem like it weighs les. This force is sometimes referred to as upthrust.


Capillaries : tiny blood vessels that connect the ends of arteries to the ends of veins.
Carbonates : chemicals containing combinations of carbon and oxygen with some other element, such as calcium, barium, or manganese
Cathodes : the negative electrode of an electrolytic cell; the positive terminal of a cell that is producing electrical energy by a chemical process that cannot be reversed.
Cell : the smallest units or building blocks of all living things
Cell Membrane : the thin, film like outer layer that holds a cell together and separates it from its environment, and allows materials to pass into and out of the cell
Cell Wall : outermost layer of a cell
Cementation : a process of rock layer formation in which water is squeezed out, leaving minerals that glue the sediments together
Center of Gravity : the point on an object at which its weight seems to be concentrated so that the object would balance if supported at this point
Centripetal Force : the unbalanced force which acts towards the center and keeps the body in a circular path
Charles’s Law : the volume of a fixed mass of gas is directly proportional to its absolute temperature if the pressure is kept constant.
Chemical Indicators : a substance, such as litmus, that is used to determine the presence of an acid or a base.
Chemical Particles : the atom or molecules that make up minerals and all matter
Chemical Weathering : the breakdown of rocks by changes in their chemical compositions

Chloroplast : the part of a plant cell where chlorophyll is stored and food is made
Chlorosis : the loss of green color in plants
Chromatography : a method of separating a mixture into its parts
Cleavage : the property of a mineral that allows it to break along a cleavage plane, exposes two smooth edges
Cleavage Plane : a flat smooth area in minerals along which the bonds between atoms are relatively weak
Cohesive Force : the force that exists between like molecules
Condense : to change from a gas to a liquid by cooling.
Conduction : is the flow of heat through matter from places of higher to places of lower temperature without movement of the matter as a whole
Coulomb : is the charge passing any point in a circuit when a steady current of one ampere flows for one second.
Convection : is the flow heat through a fluid from places of higher places of lower temperature by movement of the fluid itself
Cotyledons : the two halves of a seed that are actually simple leaves; also called seed leaves.
Crystal : a solid material in which the atoms or molecules are arranged in a repeating pattern
Current : the steady movement of the ocean’s surface water in a certain direction; caused in part by winds
Cytoplasm : a grayish jellylike material made mostly of water that fills a cell, and which the other parts of the cell float


Density : a measure of how much material of an object is packed into a given volume, calculated by dividing the mass of an object by its volume.
Diffraction : Change in the directions and intensities of a group of waves after passing by an obstacle or through an aperture whose size is approximately the same as the wavelength of the waves. The bending of waves behind obstacles into the shadow region
Displacement : is the distance moved in a stated direction and is a vector quantity


Eclipse : the passing of one body in front of another, cutting off its light
Ectothermic : having a body temperature that changes with the temperature of the environment
Electron : the negatively charged particles spinning around the nucleus of an atom
Electromotive force (e.m.f) : of a source of electrical energy is the energy it supplies to each coulomb of charge flowing round the complete circiut; it equals the terminal p.d. of the source on open circuit
Electricity : a form of energy that comes from electric charges
Electrical Conductor : materials that allow electric charges to pass through them
Electrolyte : a substance whose water solution can conduct electricity
Element : A substance composed of atoms having an identical number of protons in each nucleus. Elements cannot be reduced to simpler substances by normal chemical means.
Embryo : an organism in its earliest stages of development
Endoplastid Reticulum: an intricate system of tubular membranes in the cytoplasm of a cell. It is responsible for the synthesis and transport of materials to and from cells.
Energy : the ability to cause changes in matter

Epicotyl : the part of a plant embryo located above the hypocotyl that develops into the plant’s stem, leaves flowers and fruits
Esophagus : the strong muscular tube that leads from the back of the throat to the stomach
Evaporate : to change from a liquid phase to a gas phase
Evolution : the natural or artificially induced process by which new and different organisms develop as a result of changes in genetic material


Fatty Acids: chemicals found in animal and plant fat and are composed of carbon, hydrogen and oxygen
Force : a push or pull exerted on an object in a certain direction.
Fossil Fuels : energy sources, including coal and natural gas, made of buried remains of decayed plants and animals that lived hundreds of millions of years ago
Fracturing : the breaking of a mineral across a cleavage plane, exposing uneven or jagged edges
Free-fall : the condition of unrestrained motion in a gravitational field
Friction : the force that resists relative motion between two bodies in contact


Golgi Apparatus : a membranous structure in the cytoplasm of cells consisting of layers of flattened sacs. It functions in the processing and transporting of proteins
Gravity : the force that the earth exerts on all objects


Half-Life : the time for half the atoms in a given sample to decay.
Homogeneous : being a solution that is the same throughout.
Hooke’s Law : the extension of a spring is proportional to the stretching force so long as the spring is not permanently stretched.
Hydrated : being in a state in which solute molecules are surrounded by water molecules, or in which materials, such as food cells, contain water
Hydration : process by which water molecules surround a solute molecule.
Hydrometer : an instrument used to measure the density.
Hygrometer : an instrument used to indicate changes in humidity.
Hypocotyl : the part of a plant embryo that develops into the lower stem and root.


Igneous Rock : rock produced by the cooling and solidifying of magma and lava.
Imbibitions : the process by which a hydrophilic, porous material absorbs water.
Inertia : the property of a body by which it remains at rest or continues moving in a straight line unless acted upon by a directional force.
Insulator : a material that restricts or retards the flow of heat and is therefore a poor conductor of heat.
Interference : is a phenomenon that occurs when two or more waves of the same frequency overlap.
Ion : a charged subatomic particle.
Ionized : electrically charged.
Isotopes : isotopes of an element are atoms, which have the same number of protons but different numbers of neutrons.


Joule : is the unit of work and is the work done when a force of one Newton moves through one meter.


Kinetic Energy : energy a body has by virtue of its motion


Lava : magma that has risen to the surface of the earth.
Law of Conservation of Energy : energy cannot be created or destroyed but it can be changed from one form into another.
Law of Conservation of Momentum : when two or more bodies act on one another as in a collision, the total momentum of the bodies remains constant, provided no external forces act (e.g. friction).
Law of Principle of Moments: when a body is in equilibrium the sum of the clockwise moments about any point equals the sum of the counterclockwise moments about the same point.
Lens: the part of the eye that focuses light rays.
Lenz’s Law : the direction of the induced current is such as to oppose the change causing it.
Lithosphere : the layer of earth made up of the crust and the upper portion of the mantle.
Longitudinal Waves : a wave in which the vibrations occur in the same direction as the direction of travel of the wave
Lunar eclipse : an eclipse of the moon that occurs when earth comes between the sun.
Lysosome : a membrane-bound cavity in living cells that contains enzymes that are responsible for degrading and recycling molecules. They can deal with material both originating within the cell and entering from outside, and are especially important in the immune cells that ingest and degrade bacteria


Magma : liquid rock beneath earth’s surface.
Mantle : the layer of earth beneath the crust.
Mass Number : of an atom is the number of nucleons in the nucleus. Also known as the nucleon number and represented by the letter A.
Melting : the change to a solid to liquid as a result of an increase in energy.
Mineral : a substance found in the ground that does not come from living things, and has a definite chemical composition and a regular crystal form.
Mitochondria : a small round or rod-shaped body that is found in the cytoplasm of most cells and produces enzymes for the metabolic conversion of food to energy
Mixture : a physical combination of two or more substances.
Molecules : the smallest particle of a substance that retains all the properties of the substance and is composed of one or more atoms.
Momentum : the quantity of the motion in a body that is moving. It is measured in kilogram meters per second
Morse Code : A code made up of dots and dashes. This code was used to communicate by telegraph.


Neutral : chemicals that are neither an acid nor a base.
Neutron : the neutrally charged particles in the nucleus of an atom.
Nuclear Change : a change in the nucleus of an atom in the process of transmutation, resulting in the release of energy and matter.
Nucleus : (1) the central part of the head of a comet.
(2) the control center that directs all the activities of a cell.
(3) the positively charged center of an atom, which contains protons and neutrons.


Overfishing : the act of removing fish from the water faster than they can be reproduced and be replaced.


Partial Solar Eclipse : an eclipse in which part of the light of the sun is blocked by the moon.
Penumbra: the lighter part of a shadow.
Periodic Table : a tabular arrangement of the elements
Peristalsis : muscle contractions inside the body to move substances, such as food, along.
Phloem Tubes : the tubes in a plant that transport sap containing water and food manufactured in the leaves throughout the plant and down to the root where it is stored.
Photosynthesis : a process by which green plants and other organisms produce simple carbohydrates from carbon dioxide and hydrogen, using energy that chlorophyll or other organic cellular pigments absorb from radiant sources
Physical Change : a change in the appearance in matter, but not in the properties and makeup.
Pigment : a substance that colors and can protect an organism from ultraviolet light; used by plants to make food.
Pitch : the property of a sound and especially a musical tone that is determined by the frequency of the waves producing it: highness or lowness of sound.

Plastid : a specialized organ or part in a photosynthetic plant cell that contains pigment, ribosomes, and DNA, and serves specific physiological purposes such as food synthesis and storage
Plumule : the tiny immature leaves at the end of the epicotyl, which develop into the plant’s first true leaves.
Potential : the potential at a point is the work done per coulomb to bring positive charge from Earth to the point.
Potential Energy : energy a body has by virtue of its position or state
Potential Difference : the potential difference between two points in an electric field is the work done (or energy changed) per coulomb to move positive charge from one point to the other.
Power : the rate at which energy is changed from one form to another. The unit of power is the watts
Predator : an animal that kills other animals for food.
Pressure : is the force acting on unit area. The unit of pressure is the Pascal.
Pressure Law : the pressure of a fixed mass of gas is directly proportional to its absolute temperature if the volume is kept constant.
Principle of Flotation : a floating body displaces its own weight of fluid.
Protons : the positively charged particles in the nucleus of an atom.


Radicle : the tip of a hypocotyl, which develops into roots.
Radiation : is the flow of heat from one place to another by means of waves i.e. energy in the form of rays or waves. Also, energy given off when radioactive elements decay.
Radioactive Decay : the breakdown of an unstable nucleus of an atom.
Radioactive Element : elements who atoms undergo radioactive decay.
Rarefaction : the least dense part of a sound wave.
Reaction Force : a force equal to an action force, but in the opposite direction.
Reef : A solid structure built of shells and other secretions of marine organisms, particularly coral.
Refraction : The turning or bending of any wave, such as a light or sound wave, when it passes from one medium into another of different optical density.
Rehydrating : changing a dehydrated material to a hydrated form by restoring water to the material.
Resonance : The increase in amplitude of oscillation of an electric or mechanical system exposed to a periodic force whose frequency is equal or very close to the natural undamped frequency of the system.
Resultant Force : is a single force that represent two or more forces acting at a point.
Ribosome : cluster of proteins and RNA that takes part in the manufacture of proteins.
Richter Scale : A logarithmic scale for expressing the magnitude of an earthquake in terms of the energy dissipated in it. A modified version of this scale is commonly used.
Rust : iron oxide formed by the oxidation of iron in the presence of water.


Salinity : the amount of salt in water
Satellite : a body that orbits a celestial body, including natural satellites (such as moons orbiting planets) and manufactured satellites (such as weather satellites orbiting Earth).
Scalar Quantity : a quantity that has only magnitude.
Sediment : regolith that has been transported by agents of erosion and deposited in another place.
Solute : a material that dissolves in a solvent.
Solution : a combination of a solute and a solvent.
Solvent : the material in which a solute dissolves.
Specific Gravity : the ratio of the mass of a substance compared to the mass of an equal volume of water.
Specific Heat Capacity : the specific heat capacity of a substance is the rate is the heat required to produce unit temperature rise in unit
Specific Latent Heat of Fusion : The specific latent heat of a fusion of a substance is the quantity of heat needed to change unit mass from solid to liquid without change of temperature. It is denoted as l_f.
Specific Latent Heat of Vaporization : The specific latent heat of a vaporization of a substance is the quantity of heat needed to change unit mass from liquid to vapor without change of temperature. It is denoted as l_v.

Spectrum : a band of colored lights produced when visible light is separated.
Static Charges : electric charges that are stationary.
Static Electricity : energy due to the build up of charges on an object.
Stratum : a layer of one kind of rock material.
Stridulation : the process by which some insects make sounds by rubbing body parts together.
Sublimation : the process by which a gas changes directly into a solid without becoming a liquid.
Surface Tension : the attractive force that causes the molecules of a liquid to cling together to form a skin like film at the liquid’s surface.


Tectonics : The branch of geology that deals with regional or global structures and deformational features of Earth.
Thorax : the middle body part of an insect, to which the legs and wings are attached.
Torque : is the measure of a turning effect; determined by multiplying a force times the length of its
Total Solar Eclipse : a solar eclipse in which all of the sun’s light is blocked because the moon is close enough to earth that the apparent size of the moon and the sun are the same.
Transmutation : the process by which the nucleus of an atom changes so that a new element is formed
Transverse Waves : a wave which is propagated by vibrations perpendicular to the direction of travel of the wave


Vacuole : a membrane-bound compartment containing fluid that is found in the cytoplasm of a cell
Vector Quantity : a quantity that has both magnitude and direction.
Viscosity : a measure of how fast a fluid flows


Water Cycle : the natural process by which water from oceans, lakes, soils and other sources on earth evaporates, condenses in the atmosphere to form clouds, falls back to earth in forms such as rain or snow, and returns to the oceans, lakes and soil.
Wave : allows energy to be transferred from one point to another some distance away without any particles of the medium traveling between two points.
Weight : a measure of the gravitational force pulling an object downward towards Earth’s center; also the gravitational force between two objects
Work : work is said to be done when the point of application of a force moves and is measured by the product of the force and the distance moved in the direction of the force


Xylem Tubes : the tubes in a plant that transport water and dissolved minerals upward through the roots to the rest of the plant.