Year 9 Science Exam Notes

Scientific Method

A systematic approach used in scientific research to investigate and understand phenomena.

Independent variable

The variable that is purposely manipulated or changed in an experiment, believed to have an impact on another variable.

Dependent variable

The variable observed as the outcome in an experiment, the variable of interest.

Experimental group

The group that receives the special treatment or intervention in an experiment.

Control group

The group that does not receive the experimental treatment and is used as a baseline for comparison.

Accuracy

How close measurements are to the true value.

Validity

If an experiment measures what it needs to measure in the right way.

Reliability

The consistency, stability, and repeatability of measurements, observations, or tests over time.

Fairness

The ethical and equitable treatment of all participants or subjects involved in research.

Systematic errors

Consistent and repeatable errors that consistently push measurements away from the true value.

Random errors

Unpredictable and inconsistent fluctuations caused by various unpredictable factors.

Biotic factors

Living or once-living components of an ecosystem that can directly or indirectly affect other organisms.

Abiotic factors

Non-living physical and chemical components of an ecosystem that influence organisms and the environment.

Photosynthesis

The process in which green plants, algae, and some bacteria convert energy, carbon dioxide, and water into glucose and oxygen.

Producers

Organisms that can synthesize their own organic molecules.

Consumers

Organisms that obtain energy and organic molecules by consuming other organisms.

Detritivores

Organisms that feed on dead organic matter and break it down into smaller parts.

Decomposers

Microorganisms that break down complex organic matter into simple substances.

Central Nervous System (CNS)

The core component of the nervous system, located within the skull and vertebral column, responsible for processing and control.

Peripheral Nervous System (PNS)

All the nervous tissue outside the CNS, facilitating connection between the CNS and the rest of the body.

Sensory neurons

Neurons that transmit information from sensory receptors to the central nervous system.

Motor neurons

Neurons that transmit signals from the central nervous system to muscles, glands, and other effectors.

Voluntary (somatic) responses

Responses made under conscious control, initiated and regulated by the somatic nervous system.

Automatic (autonomic) responses

Responses not made under conscious control, regulated by the autonomic nervous system.

Cell body (soma)

Contains the nucleus and organelles necessary for cellular functions in a neuron.

Dendrites

Branched extensions that receive incoming signals in a neuron.

Axons

Long, slender extensions that transmit electrical signals away from the cell body to other neurons or target cells.

Synapses

Junctions where the axon endings are near the dendrites of another neuron or target cell, sites of communication.

Hormones

Chemical messengers that regulate physiological processes and maintain balance in the body.

Frontal lobe

Controls emotions, decision-making, behavior, and memories.

Parietal lobe

Controls senses, attention, and language.

Occipital lobe

Controls eyesight and processes visual information.

Temporal lobe

Controls speech, memory, language comprehension, and hearing.

Cerebrum

Responsible for thinking, memory, and sensory perception.

Hypothalamus

Keeps the body in a stable state called homeostasis.

Pituitary gland

Regulates growth, metabolism, and reproduction.

Cerebellum

Controls balance, posture, and coordination.