Year 8 Science CAT 2 Revision: Graphing & Depth Study

Vocabulary-style flashcards covering graphing rules, experimental variables, scientific investigation terms, and basic chemistry concepts for the Year 8 Science CAT 2 exam.

Independent Variable

The thing you changed on purpose in an experiment, placed across the bottom of a graph.

Dependent Variable

The thing you measured as a result of an experiment, placed up the side of a graph.

SPLAT

An acronym for checking a graph: Scale, Plots, Line of best fit, Axes, and Title.

Scale (Even steps)

A graphing rule where every square must be worth the same amount (e.g., $0, 10, 20, 30$).

Scale (Fill the grid)

A graphing rule where data points must take up more than half the grid both across and up.

Plots

Small neat crosses placed exactly on the value on a graph.

Line of best fit

ONE straight line drawn with a ruler through the middle of the points; it is never dot-to-dot and does not have to touch any point.

Axes labeling

The requirement that both sides of a graph are labeled and include units.

Title (Graphing)

A label for a graph typically written as "The effect of [Independent Variable] on [Dependent Variable]".

Trend Description

A sentence identifying direction (increase/decrease/stay the same) and providing evidence using numerical values and units.

Interpolate

Reading a value inside the data range between points that were actually measured.

Extrapolate

Carrying a line of best fit past the last measured point to make a prediction outside the data range.

Aim

A statement of purpose written as "To investigate how [Independent Variable] affects [Dependent Variable]".

Hypothesis

A prediction written as "If [Independent Variable] increases, then [Dependent Variable] will [change]".

Validity

The extent to which an experiment tests the right thing by changing only the Independent Variable and keeping everything else controlled.

Reliability

The consistency of results, achieved by repeating an experiment $3+$ times, getting results close together, and calculating an average.

Accuracy

How close a number is to the truth, ensured by using good equipment, finer scales, careful technique, and calibration.

Signs of a Chemical Reaction

Evidence such as bubbles/gas, color change, temperature change, the formation of a precipitate, or being hard to reverse.

Precipitate

A solid that forms in a liquid during a chemical reaction.

Exothermic Reaction

A reaction where heat comes out, the surroundings get hotter, and the temperature goes up.

Endothermic Reaction

A reaction where heat goes in, the surroundings get colder, and the temperature goes down.

Method Checklist

A five-step guide for fairness: Set it up, Change ONE thing, Keep the rest the same, Measure and record, and Repeat.

Evidence

In Science questions, this term specifically requires providing at least two figures from the data.