FREE Density Mystery | Science After the Fact: Wayward Balloons

The Description

Two balloons in water. One floats, the other sinks. The experiment is already over, and students have to work backward from the evidence.

This free Science After the Fact density mystery asks students to investigate what the observations and particle models can reveal about thermal expansion. No dramatic demonstration required; the tricky part is explaining what happened.

What Students Will Do

• Examine observations from the completed balloon experiment.

• Interpret particle models and practice density calculations.

• Decide which evidence matters to the mystery.

• Construct a scientific explanation that links particle behavior and density.

Why This Resource Is Different

Students can calculate density flawlessly and still have no idea why temperature changes a fluid's behavior.

Here the calculation is a clue, not the destination. Their explanations show whether the particle-level story and the math are actually connected.

What's Included?

• Two-page student activity PDF.

• Teacher directions and suggested-response PDF.

• Inquiry Starter Kit PDF included in the existing download.

The Details

Free; grades 7–10; printable PDFs.

Use as a density review or follow-up to particle models and thermal expansion.