Grade 8 General Science key terms

Information obtained through appropriate senses or instruments, separated from the explanation proposed to account for it.

A testable proposed explanation or prediction that can be compared with evidence rather than treated as established fact.

The condition deliberately varied in an investigation so its relationship with a measured outcome can be examined.

The measured outcome examined in relation to a changed condition while other relevant influences are considered.

An important condition kept comparable across a test so differences are easier to interpret within the investigation.

The smallest displayed or distinguishable increment of an instrument, which is not the complete uncertainty of a measurement.

A representation of matter using particles and their arrangement or motion to explain selected physical observations.

A change such as melting that need not alter the chemical identity of the substance being described.

A process rearranging atoms into different chemical substances while conserving atoms in a correctly balanced account.

A basic unit of an element that can participate in bonds and chemical rearrangement without becoming a different element.

A basic unit of living organization with structures and processes that support the functions of an organism.

The breakdown of food into forms that can be absorbed, distinguished from simply transporting substances through the body.

Cellular chemical processes releasing usable energy, which must not be reduced to the movement of air during breathing.

A process using light energy to support the production of organic substances from appropriate inorganic inputs in photosynthetic organisms.

An organism building organic matter from inorganic sources using light or chemical energy within the relevant ecological system.

An organism obtaining organic matter by feeding on other organisms or their products within a food relationship.

An organism involved in breaking down organic material and returning substances to pathways of nutrient cycling.

A representation of connected feeding relationships whose arrows should be interpreted according to the stated transfer convention.

Conversion of atmospheric nitrogen into ammonia or related ammonium forms, distinguished from the later processes of nitrification.

Biological oxidation processes converting reduced nitrogen toward nitrite and nitrate under suitable conditions in the nitrogen cycle.

Movement of energy between parts of a system, distinguished from a claim that all energy remains equally useful.

A mechanical disturbance transferring energy through a material medium rather than traveling as sound through a vacuum.

Escape of particles from a liquid surface into the gas phase, which can occur without the whole liquid boiling.

Organisms and their physical environment considered through interactions, material cycling and energy transfers within a defined system.