ACT Science vocabulary: measurement and mathematical relationships.

correct; free from errors or mistakes; precise.

The survey produced an accurate estimate because researchers checked every response twice before publishing the results.

Memory cueAn accurate arrow strikes the precise center without error.

Corresponding in size or degree; in proportion

The salary offered was not commensurate with the level of experience required for the position.

Memory cueCommensurate scales balance because reward corresponds proportionally to effort.

The condition of being equal or interchangeable in value, function, or meaning

The mathematician proved the equivalence of the two theorems, showing that each could be derived from the other.

Memory cueEquivalence places two things on equal, interchangeable sides of a balance.

At an increasingly rapid rate; by a very large amount

Data storage costs have decreased exponentially over the past three decades, transforming entire industries.

Memory cueExponential growth climbs faster each step, multiplying instead of adding.

having limits or bounds

Earth's resources are finite, making the scale or scope of the subject easier to understand through comparison.

Memory cueA finite road has marked boundaries and a definite end.

The rate at which a measured quantity changes across distance or another continuous dimension.

A steep temperature gradient developed between the heated surface and the cooler bottom layer.

Memory cueA gradient is a change ramp: steep ramps show rapid change across distance.

extremely large or great; huge.

The immense desert stretched endlessly, helping the audience recognize how much of the larger subject it represented.

Memory cueAn immense object stretches far beyond the frame.

limitless or endless in space or time

The universe may be infinite in extent, helping the audience recognize how much of the larger subject it represented.

Memory cueAn infinite road continues beyond every horizon without limit.

Able to be exchanged with each other; essentially identical

The parts were designed to be interchangeable , so that a broken component could be replaced without custom fabrication.

Memory cueInterchangeable parts trade places while the machine continues working the same way.

Opposite in position, direction, order, or effect

The study revealed an inverse relationship between screen time and academic performance among adolescents.

Memory cueAn inverse relationship points one arrow up as the other goes down.

Following a constant rate of change that forms a straight line when graphed.

The graph is linear because pressure rises by the same amount with each temperature increase.

Memory cueLINE hides inside linear; a constant rate draws a straight graph line.

extremely small

Only minute traces were detected, making the scale or scope of the subject easier to understand through comparison.

Memory cueA minute detail is so tiny that a lens must enlarge it.

So small or unimportant as to be not worth considering; insignificant

The difference in cost between the two options was negligible , so the committee chose the more sustainable one.

Memory cueA negligible amount shrinks into a speck too small to matter.

Not following a constant rate of change and therefore not forming a straight graph line.

The population showed nonlinear growth as limited food gradually slowed the rate of increase.

Memory cueA nonlinear relationship bends away from the ruler because its rate keeps changing.

exact; clearly expressed; strictly defined.

The surgeon's precise movements were impressive, showing whether a clear structure guided the activity as conditions became more demanding.

Memory cueA precise point lands exactly on the target's center.

Changing at a constant ratio so that one quantity scales directly with another.

The extension of the spring remained proportional to the applied force throughout the tested range.

Memory cueOn a proportional seesaw, multiplying one quantity multiplies the other by the same factor.

A comparison of two quantities expressed by dividing one amount by the other.

The ratio of nitrogen atoms to hydrogen atoms remains one to three in every ammonia sample.

Memory cueA ratio places two quantities on opposite sides of a comparison colon.

At the same time; concurrently

The orchestra's ability to play softly and intensely simultaneously created a tension that held the audience spellbound.

Memory cueTwo clocks striking simultaneously sound at exactly the same time.

of considerable importance, size, or worth; solidly built

The company made a substantial investment in new technology, helping the audience recognize how much of the larger subject it represented.

Memory cueA substantial block is large, solid, valuable, and too important to ignore.

not changing in form or character; remaining the same in all cases and at all times. (Also a noun for a distinctive clothing worn by members of a group.)

The company implemented uniform policies across all its branches, giving observers a more precise basis for comparing the two subjects.

Memory cueA uniform pattern remains identical throughout; a uniform outfit marks group membership.