Mastering Scientific Investigation Principles for the ACT Science Test

Scientific Investigation

Category on the ACT Science test focused on understanding experimental tools and procedural logic.

Precision Tools

Instruments like graduated cylinders or balances used to measure quantities with high precision.

Environment Controllers

Tools used to manipulate the environment, such as hot plates or ice baths.

Calorimeter

A tool used to measure heat transfer in an experiment.

Independent Variable (IV)

The factor that is intentionally changed in an experiment; plotted on the x-axis.

Dependent Variable (DV)

The factor being measured or observed in response to the IV; plotted on the y-axis.

Controlled Variables

Factors kept the same across all trials to ensure a fair test.

Control Group

A specific trial used as a baseline standard for comparison in an experiment.

Single Variable Rule

A valid experiment should change only one independent variable at a time.

Sample Size

The number of observations in an experiment; larger sizes reduce the impact of outliers.

Confounding Variables

Accidental changes in variables that should have been constants during an experiment.

Validity

The quality of an experiment that measures what it claims to measure without interference.

Homogeneity

Uniform composition of a solution achieved by stirring.

Interpolation

Predicting a value between two known data points.

Extrapolation

Predicting a value outside the known range based on established trends.

Direct Variation

A relationship where as x increases, y also increases.

Inverse Variation

A relationship where as x increases, y decreases.

Measurement Error

Using a tool that lacks sufficient precision, which can lead to inaccurate results.

Thresholds

Limits within which certain conditions are valid, such as phase changes.

Correlation vs. Causation

Noting that correlation does not imply one variable causes the other.

Unit Labels

Labels that indicate the units of measurement on tables or graphs, crucial for accurate interpretation.

Prediction

An educated guess about the outcome of an experiment based on trends and data.

Mixing Up IV and DV

Mistake of confusing independent and dependent variables in experimental data.

Overlooking Scale

Failing to recognize differences in graph scales, which can lead to misinterpretations.

Cleaning/Flushing

Rinsing containers to prevent cross-contamination between trials.