Year 9 Science Revision

Physical Change

Change affecting form, not chemical composition.

Chemical Change

Change resulting in new substances formed.

Reactants

Substances present before a chemical reaction.

Products

Substances formed after a chemical reaction.

Coefficient

Number indicating molecules' quantity in reaction.

Subscript

Number indicating atoms in a molecule.

Balanced Equation

Same number of each atom on both sides.

Conservation of Mass

Mass remains constant in chemical reactions.

pH Scale

Measures acidity or alkalinity of a solution.

Neutral pH

pH level of 7, neither acidic nor basic.

Acidic Solution

pH less than 7, contains hydrogen ions.

Basic Solution

pH greater than 7, contains hydroxide ions.

Pathogen

Agent causing infectious diseases.

Vector

Organism transmitting pathogens to hosts.

Non-specific Immunity

Innate response attacking all pathogens.

Specific Immunity

Adaptive response targeting specific pathogens.

Phagocyte

Cell that engulfs and destroys pathogens.

Inflammation

Body's response to injury or infection.

B-cells

White blood cells producing antibodies.

Memory Cells

B-cells that remember pathogens for faster response.

Antibody

Protein that binds to specific antigens.

Vaccine

Substance stimulating immune response against pathogens.

Booster Vaccine

Reinforces immunity when antibody levels drop.

Hydrogen Ions

Positively charged ions in acidic solutions.

Hydroxide Ions

Negatively charged ions in basic solutions.

Corrosion

Destruction of materials, often metals, by chemical reactions.

pH of Soap

Typically around 9, indicating basic nature.

Booster Vaccines

Administered to increase memory cells and antibodies.

Antibody Levels

Concentration of antibodies in the bloodstream.

Ecosystem Components

Biotic and abiotic factors interact within ecosystems.

Biotic Factors

Living components like plants and animals.

Abiotic Factors

Non-living components like water and soil.

Keystone Species

Species crucial for ecosystem stability and diversity.

Photosynthesis

Process converting light energy into chemical energy.

Cellular Respiration

Process of converting glucose into usable energy.

Chloroplasts

Organelles where photosynthesis occurs in plants.

Glucose

Primary energy source for living organisms.

Trophic Levels

Hierarchical levels in food chains/webs.

Producers

Organisms that create their own food via photosynthesis.

Consumers

Organisms that obtain energy by consuming others.

Carbon Dioxide Absorption

Plants absorb CO2 during photosynthesis.

CO2 Emission Processes

Respiration and combustion release CO2 into atmosphere.

Renewable Fuels

Sustainable energy sources like solar and wind.

Commensalism

Symbiotic relationship benefiting one organism only.

Symbiotic Relationships

Interactions between species affecting their survival.

Controlled Experiments

Tests designed to isolate and measure variables.

Dependent Variable

Data collected during an experiment.

Independent Variable

Factor manipulated to observe effects.

Quantitative Measurement

Data expressed numerically for analysis.

Qualitative Measurement

Data describing qualities or characteristics.

Inflammation Process

Non-specific immune response to injury or infection.

Pathogens

Microorganisms causing infectious diseases.

Vaccination

Introduction of dead pathogens to stimulate immunity.

B-Cells

Lymphocytes that produce antibodies.

Antibodies

Proteins that neutralize pathogens.