Science 8.3 Change — Word List

Year 8 Science, Topic 8.3 Change. All 36 key terms: energy and heat transfer (conduction, convection, radiation), the rock cycle and rock types, weathering, erosion and sedimentary processes, mineral properties, and physical vs chemical change including exothermic and endothermic reactions, respiration and photosynthesis. Definitions are the exact class wording.

energy

The ability to do work

joules (J)

The standard unit of work or energy in the International System of Units (SI)

potential energy

the stored energy an object or system possesses due to its position, state, or arrangement of components

kinetic energy

The energy possessed by a moving object

conduction

Heat transfer through a solid material by contact of one particle with the next

convection

The transfer of heat in fluids or gases caused by differences in density

radiation

The transfer of energy through space by waves and/or particles

rock cycle

a continuous geologic process in which Earth's three main rock types - igneous, sedimentary, and metamorphic - transform into one another over thousands to millions of years

metamorphic

Rocks that have been changed by heat and/or pressure

igneous

Rock formed by the solidification of molten magma

sedimentary

Rocks that are formed by the deposition compaction, dehydration and cementation of sediments at the Earth's surface and/or within bodies of water

weathering

Wearing away or breaking down of Earth's rocks, soils and minerals

erosion

Removal of, rock or soil particles by water, ice, and/or gravity

deposition

The action of depositing eroded particles

compaction

The process where particles of sediment are squeezed together by the weight of overlying sediment

intrusive

Igneous rock that forms below ground

extrusive

Igneous rock that forms above ground

sandstone

A sedimentary rock consisting of sand or quartz grains cemented together

conglomerate

A coarse-grained sedimentary rock composed of rounded fragments (> 2 mm) within a matrix of finer grained material.

magma

Hot fluid or semi-fluid material below or within the earth's crust

lava

Lava is what magma is called when it reaches the surface

fossil

The fossil remains of an organism that lived in a particular geologic age, used to identify or date the rock or rock layer in which it is found

superposition

The principle that any sequence of sediments or rocks that has not been overturned, the youngest sediments or rocks are at the top of the sequence and the oldest are at the bottom

mineral

Solid homogeneous inorganic substances occurring in nature having a definite chemical composition

dehydration

The process where water is squeezed out from the pores of sediments

cementation

The binding of sediments by the precipitation of mineral matter in the pore spaces

hardness

The property of being rigid and resistant to pressure; not easily scratched; measured on Moh's Scale of Hardness

lustre

The visual property of a mineral that shines with reflected light

cleavage

The splitting of rocks or crystals in a preferred plane or direction

exothermic reaction

A chemical reaction that releases energy into its surroundings, usually as heat or light

endothermic reaction

A chemical reaction that absorbs heat energy from its surroundings, causing the local area to feel colder

physical change

A physical change is a change in the size, shape, or state of matter where the core identity and chemical makeup of the substance stay completely the same

chemical change

A chemical change is a process where one or more substances turn into entirely new substances with different properties

chemical reaction

A chemical reaction is a process where starting substances, called reactants, break their chemical bonds, rearrange, and bond again to form entirely new substances, called products

respiration (aerobic)

The chemical process that living cells use to Uses oxygen to turn glucose into carbon dioxide, water, and energy (ATP)

photosynthesis

The process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar