Relative density in fluids is the focus of this Grade 6 Science worksheet, where students investigate why an object can float in one liquid and sink in another. Rather than judging objects by their size or how heavy they feel, learners use density comparisons and observations to explain floating and sinking scientifically.

Why does the same object behave differently?

The reading passage introduces density as the amount of mass packed into a given volume and explains how an object's average density compares with the density of the surrounding liquid. Students explore three possible outcomes: an object generally floats when it is less dense than the liquid, sinks when it is denser, or may remain suspended when the densities are equal.

A comparison between fresh water and a denser saltwater solution helps students connect the concept to an observable situation. The object itself does not change, but the surrounding liquid does. This distinction encourages learners to consider the properties of both the object and the fluid when predicting what will happen.

Build evidence-based explanations

The activities move beyond recalling a definition. Students interpret scenarios involving objects in different liquids, identify information needed to predict floating or sinking, and evaluate how to compare liquids fairly. They also examine why a heavy-feeling object does not necessarily sink in every liquid and how controlled testing makes scientific conclusions more reliable.

The worksheet includes multiple-choice questions, true-or-false statements, short-answer explanations, a labelled diagram activity, a categorization task, and a short-note activity. Written responses ask students to explain differences in floating behaviour, challenge the assumption that weight alone determines an outcome, and describe how to keep an investigation fair.

What is included

• Student worksheet: A reading passage and activities about density, liquid comparisons, floating and sinking, and fair investigations.
• Separate PDF answer key: A reference for checking student responses.
• Student Notes lines: Space at the bottom of the worksheet for recording key ideas.
• Teacher Guide: Included in the Answer Key PDF, with Learning Objectives, Teaching Tips, Discussion Questions, and Common Mistakes.

Ways to use this worksheet

Use this relative density practice during a Grade 6 unit on matter and its properties, as independent classwork, for review after a demonstration, or to check students' explanations before a hands-on investigation. The questions provide opportunities to discuss why the same object may behave differently across liquids and why controlled conditions matter when comparing observations.

This resource is listed under Texas Science 6: Matter and Its Changes and identifies TEKS as its framework. It offers a focused way to reinforce density concepts while helping students support predictions with evidence instead of relying on appearance, size, or perceived weight alone.