Nature of Science and Experimental Design Study Guide

Fact

An objective, verifiable observation about the world, such as water boiling at $100 failure^\times \rightarrow 100^\text{o}\text{C}$ or $100 tribunal^\text{o}\text{C}$.

Principle

A statement based on repeated experimental observation that describes an aspect of the world.

Law

A broad concept or principle in nature that describes patterns (HOW something happens) and is often accepted as fact.

Theory

An explanation of an observed phenomenon that organizes facts and research to explain WHY something happens; it never becomes a fact or law.

Observation

A description of something you can see, smell, touch, taste, or hear. It must be objective and not an opinion.

Inference

A guess or conclusion about an object or outcome based on prior observations.

Qualitative Data

Data that describes qualities or characteristics using descriptions rather than numbers.

Quantitative Data

Data that uses numbers to measure something, such as a length of $4\,\text{ft}$ or a mass of $7.2\,\text{g}$.

Independent Variable (IV)

The factor in an investigation that the experimenter deliberately changes or manipulates (the cause), plotted on the x-axis.

Dependent Variable (DV)

The factor that changes in response to the independent variable and is measured (the effect), plotted on the y-axis.

Control Group

The group in an experiment used for comparison, representing the normal or baseline conditions.

Experimental Group

The group or groups in an experiment that receive the variable being tested.

Constants

Aspects of an experiment that are kept identical across all groups to ensure only the independent variable affects the dependent variable.

Precision

How close repeated scientific measurements are to each other, indicating consistency and specificity.

Accuracy

How close a measured value is to the correct or accepted true value.

Law

A broad concept or principle that describes patterns in nature and explains how things happen.

Theory

An explanation of an observed phenomenon that organizes facts and research to explain why something happens; it never becomes a law.

Observation

A objective description of something you can see, smell, touch, taste, or hear.

Inference

A guess or conclusion about an object or outcome based on prior observations.

Qualitative Data

Data that describes non-numerical qualities or characteristics, such as color or taste.

Quantitative Data

Data that uses numbers to measure quantities, such as mass or length.

Independent Variable (IV)

The single factor that the experimenter deliberately changes or manipulates in an investigation.

Dependent Variable (DV)

The factor that changes in response to the independent variable; what is measured in the experiment.

Control Group

The baseline group used for comparison in an experiment, representing the normal condition.

Constants

The aspects of an experiment that are kept completely identical across all groups to ensure valid results.

Precision

How close repeated measurements are to each other, indicating consistency.

Accuracy

How close a measured value is to the correct or accepted true value.