Junior Secondary Science Syllabus (Form One and Form Two)

Vocabulary practice flashcards covering Junior Secondary Science syllabus topics including scientific processes, laboratory apparatus and safety, physical measurements, cell biology, human anatomy, ecology, chemistry, and genetic technology.

Science

A way of finding out how things happen so that we can understand the world around us, consisting of biology, chemistry, and physics.

Technology

The practice of making machines, objects, and systems to meet people's needs, involving design, invention, production, and values.

Hypothesis

A possible answer or explanation to a scientific question, often described as an intelligent guess.

Fair test

An experiment in which only one factor is changed so that the results of the experiment are unquestionable and valid.

Independent variable

The variable of interest that is deliberately changed in an investigation while all other possible variables remain constant.

Dependent variable

The variable that is observed or measured to see if it is affected by changes in the independent variable.

Control group

The group used as a standard of comparison against the experimental group to determine whether a change has occurred.

Laboratory safety symbols

Warning labels placed on hazardous substances indicating specific risks such as toxic, highly flammable, harmful or irritant, explosive, oxidising, and corrosive.

Heating flammable liquids

The procedure of placing a container of flammable liquid (such as alcohol) inside a beaker of water (water bath) to heat it slowly, rather than exposing it directly to an open flame.

Diluting concentrated acid

The safety rule of always adding concentrated acid slowly into water, and never adding water to concentrated acid, to prevent excessive heat production that could cause liquid to violently shoot out.

Wafting

The proper laboratory technique of using one's hand to direct chemical fumes toward the nose rather than inhaling directly from a container.

Scalar

A physical quantity that has size (magnitude) but no direction, such as time, temperature, volume, and density.

Vector

A physical quantity that possesses both size (magnitude) and direction, such as velocity, acceleration, and force.

Parallax error

A measurement error that occurs when reading the scale of a thick instrument (such as a ruler or measuring cylinder) from an angle rather than directly at eye level.

Meniscus

The upward curve formed by a liquid at the sides of a narrow container; accurate volume readings must be taken from the bottom of this curve at eye level.

Displacement can

An apparatus with a spout filled with water up to the spout level used to determine the volume of an irregularly shaped object by measuring the displaced water that overflows into a measuring cylinder.

Density

The mass per unit volume of a material, calculated as $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$, with standard units such as $\text{kg/m}^3$ or $\text{g/cm}^3$.

Hydrometer

An instrument consisting of a weighted glass tube with a scale used to measure the density of liquids based on the depth to which it sinks.

Clinical thermometer

A temperature-measuring instrument featuring a narrow constriction (bend) near the bulb that prevents mercury from falling back before the reading of a patient's body temperature is recorded.

Vertebrates

Animals that possess an endoskeleton containing a backbone or vertebral column, classified into mammals, birds, reptiles, amphibians, and fish.

Invertebrates

Animals that lack a backbone, including groups such as arthropods, molluscs, roundworms, flatworms, starfish, and jellyfish.

Cuticle

The hard outer skeleton (exoskeleton) found outside the body of insects that provides support and protection.

Cell membrane

A selectively permeable layer enclosing the cell contents that regulates the passage of substances into and out of the cell.

Chloroplasts

Plant cell organelles containing the green pigment chlorophyll, which traps light energy to enable the process of photosynthesis.

Tissue

A group of similar cells working together to perform a specific function within an organism.

Organ

A distinct structure made of several types of tissues grouped together to perform a specialized physiological function.

Photosynthesis

The process by which plants, some bacteria, and protistans synthesize glucose and release oxygen from water and carbon dioxide using sunlight trapped by chlorophyll ($6\text{H}_2\text{O} + 6\text{CO}_2 \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$).

Respiration

The chemical process taking place in mitochondria whereby cells break down glucose using oxygen to produce energy, water, and carbon dioxide.

Transpiration

The loss of water vapor from the leaves of a plant through microscopic pores called stomata.

Anomalous expansion of water

The unique behavior of water whereby it contracts upon cooling down to $4^\circ\text{C}$, but expands as it is cooled further from $4^\circ\text{C}$ to $0^\circ\text{C}$, causing ice to have a lower density than liquid water.

Acid

A proton donor that dissolves in water to give a pH of less than $7$, tastes sour, and turns blue litmus paper red.

Base

A substance with a pH greater than $7$ that reacts with an acid to produce only a salt and water.

Alkali

A water-soluble base that has a pH greater than $7$, feels slippery to the touch, tastes bitter, and turns red litmus paper blue.

Universal indicator

A solution composed of several indicators that exhibits a continuous range of colors to signify the exact pH strength of a solution from $1$ to $14$.

Abstinence

A natural contraceptive method involving complete avoidance of sexual intercourse, which is $100\%$ effective against both pregnancy and sexually transmitted infections.

Vasectomy

A permanent surgical contraceptive procedure for males in which the sperm ducts are cut and tied to prevent sperm from passing into the urethra.

Laparotomy (tubal ligation)

A permanent surgical contraceptive procedure for females in which the oviducts (fallopian tubes) are cut and tied to prevent sperm from reaching the egg.

Communicable diseases

Infectious illnesses caused by microscopic pathogens (bacteria, viruses, fungi, or protozoa) that can be passed directly or indirectly from one individual to another.

Vector

An organism, such as a housefly or an Anopheles mosquito, that carries and transmits disease-causing germs from an infected host to a healthy individual.

Enzyme

A biological catalyst that accelerates chemical reactions and metabolic processes, such as digestion, without being consumed.

Villi

Microscopic, finger-like projections along the inner lining of the small intestine that increase surface area for the diffusion and absorption of digested nutrients into the bloodstream and lymph.

Alveoli

Microscopic, elastic air sacs located in the lungs surrounded by dense capillary networks where respiratory gas exchange occurs across a single-cell thin epithelium.

Fuse

An electrical safety component containing a thin strip of metal designed to melt and open an electrical circuit when the current exceeds a predetermined rating, preventing fires.

Strip switch (circuit breaker)

A reusable electrical safety device that trips off automatically to open a circuit during an electrical overload, capable of being switched back on after resolving the fault.

Lithosphere

The solid subsystem of Earth consisting of the crust, the semi-solid mantle, and the molten outer and solid inner core.

Hydrosphere

The planetary subsystem comprising all of Earth's solid, liquid, and gaseous water, ranging from $10\,\text{km}$ to $20\,\text{km}$ in thickness.

Biosphere

The sphere of Earth containing all living organisms—including plants, animals, and microorganisms—organized into diverse ecological biomes.

Atmosphere

The gaseous envelope surrounding Earth that extends over $10{,}000\,\text{km}$ above the surface, providing weather regulation and UV protection.

Gene

The smallest unit of inheritance located at a specific locus on a chromosome, consisting of a DNA segment that directs cellular protein production and phenotypic traits.

Genetic engineering

The technology involving the direct manipulation and alteration of an organism's genetic material (DNA) to introduce desirable traits or produce targeted biological products.

Biological magnification

The phenomenon in which the concentration of non-biodegradable chemical pollutants (such as pesticides) progressively increases in organism tissues at successively higher trophic levels.

Trophic level

A distinct feeding position within a food chain or ecological pyramid, commencing with primary producers at the first level and progressing to primary, secondary, and tertiary consumers.