Grade 6 Science: Measuring Matter, Acids and Bases, and Syllabus Review

Vocabulary practice flashcards covering measurement systems, mass, weight, vernier calipers, volume, density, temperature, acids, bases, pH, neutralization, and Grade 6 science syllabus topics.

Measurement

A way to describe objects and events with numbers to answer questions such as how much, how long, or how far.

Hand Span

An ancient unit of measurement defined as the distance between the tip of the thumb and the tip of the little finger.

Cubit

An ancient unit of measurement defined as the distance between the middle finger and the elbow, equal to about $45\,\text{cm}$ or $18\,\text{inches}$.

Pace

An ancient unit of measurement defined as the distance spanned by a step, equal to about $30\,\text{inches}$.

International System of Units (SI)

The internationally accepted metric system of standard measurements (Système International) used by scientists worldwide to communicate research and lab results without confusion.

Mass

The measurement of the amount of matter in an object, which does not change with location even if gravity changes; its SI unit is the kilogram ($\text{kg}$).

Weight

A measure of the force of gravity acting on an object, measured in newtons ($\text{N}$) and calculated on Earth as $\text{Weight (N)} = \text{mass (kg)} \times 9.8\,\text{m/s}^2$.

Vernier Caliper

An instrument introduced in 1631 by Pierre Vernier for making precise linear measurements, featuring internal and external jaws, a main scale, a sliding vernier scale, and a depth measuring blade.

Vernier Constant (Least Count)

The smallest value measurable by a vernier caliper, calculated as $1\,\text{main scale division} - 1\,\text{vernier scale division} = 1\,\text{mm} - 0.9\,\text{mm} = 0.1\,\text{mm}$ ($0.01\,\text{cm}$).

Volume

The amount of space that matter occupies, measured in liters ($\text{L}$), milliliters ($\text{mL}$), or cubic centimeters ($\text{cm}^3$), where $1\,\text{mL} = 1\,\text{cm}^3$.

Water Displacement Method

A procedure used to calculate the volume of an irregularly shaped object by submerging it in water and measuring the volume of water displaced.

Density

The mass per unit volume of a material, calculated using the formula $\text{density} = \frac{\text{mass}}{\text{volume}}$ and often expressed in $\text{g}\cdot\text{cm}^{-3}$.

Rate

The amount of change in one measurement that takes place in a given amount of time, calculated by dividing a measurement by an amount of time (e.g., speed as distance divided by time).

Temperature

A measure of the average kinetic energy of all particles within an object, indicating how hot or cold it is; its SI unit is the Kelvin ($\text{K}$).

Absolute Zero

The lowest possible theoretical temperature, defined as $0\,\text{K}$ (or $-273\,^\circ\text{C}$), where particles have minimum kinetic energy.

Acid

A solution that has an excess of hydrogen ions ($\text{H}^+$), originating from the Latin word "acidus" meaning sharp or sour.

Properties of Acids

Observable characteristics including a sour taste, electrical conductivity, corrosive ability, turning blue litmus paper red, reacting with carbonates to produce $\text{CO}_2$, and reacting with metals to produce $\text{H}_2$ gas.

Indicator

A chemical compound that changes color when it comes into contact with an acid or a base (e.g., litmus paper turning red in acid and blue in base).

Acid Rain

Precipitation created when sulfur dioxide ($\text{SO}_2$) and nitrogen oxides ($\text{NO}_2$) from burning fossil fuels dissolve in moisture in the air to form sulfuric and nitric acids.

Base

A solution that has an excess of hydroxide ions ($\text{OH}^-$) or any substance capable of accepting hydrogen ions ($\text{H}^+$).

Alkali

A water-soluble base that dissolves in water to produce an alkaline solution rich in hydroxide ions ($\text{OH}^-$).

Properties of Bases

Observable characteristics including a slippery feel, bitter taste, corrosive ability, electrical conductivity, absence of reaction with metals, and turning red litmus paper blue.

pH Scale

A measurement scale ranging from $0$ to $14$ that reflects the concentration of hydrogen ions in a solution; values below $7$ are acidic, $7$ is neutral, and values above $7$ are basic.

Strong Acid

An acid whose molecules completely dissociate (fully ionize) into ions in water solution, such as hydrochloric acid ($\text{HCl}$) and sulfuric acid ($\text{H}_2\text{SO}_4$).

Weak Acid

An acid in which only a small fraction of molecules break up (partially ionize) into ions in water solution, such as ethanoic acid ($\text{CH}_3\text{COOH}$) and carbonic acid ($\text{H}_2\text{CO}_3$).

Neutralization

A chemical reaction between an acid and a base that produces a salt and water ($\text{Acid} + \text{Base} \rightarrow \text{Salt} + \text{Water}$), decreasing the acidity or basicity of the solution.

Salt

An ionic compound formed during a neutralization reaction, composed of the positive ion from a base and the negative ion from an acid.

Saponification

The specific acid-base chemical reaction between a weak acid (fatty acids) and a strong base that produces soap (an alkali salt).

Physical Balance

A laboratory instrument designated in the syllabus to measure mass and weight.

Symbiosis

Interactions among organisms identified in the Grade 6 syllabus, categorized into mutualism, commensalism, and parasitism.

Energy Roles (Ecosystem)

The functional nutritional roles that organisms fulfill within an ecosystem's energy flow, categorized as producers, consumers, and decomposers.