Gases & Liquids: Buoyancy

Discover a technique, Archimedes Principle, for easily determining the buoyant force on an object submerged in a fluid. Then use Archimedes Principle to predict whether an object will float or sink.

A. Principle

Motion Sensors

Students tabulate data based on known samples, then use the information to extrapolate the behavior of the unknown. Enlarge graph.

Lab Summary:

Students will use two Force Sensors to discover the relationship between the buoyant force on various incompressible, nonabsorbent objects immersed in water and the weight of the water displaced.

They will discover that a floating object is supported by a buoyant force equal to the object's weight and use this knowledge to predict whether a new object will float or sink.

Download free labs:

(student versions)

Computer-based lab (PDF, 756 KB)

Xplorer GLX-based lab (PDF, 1.7 MB)

Method:

Use a Force Sensor to measure the buoyant force on a fully submerged object. Measure the weight of the displaced water. Compare the buoyant force to the weight of the displaced water.

Here's What You Need:

Required for computer-based lab:

(See lab download for Xplorer GLX-based lab requirements, which may differ)

Probeware

Other Materials

Lab Manual:

The computer-based activity is included in Explorations in Physics (PS-2810). The Xplorer GLX-based lab is included in Physics with the Xplorer GLX (PS-2826). Both manuals are complete with Teacher Information pages, student instructions and handouts, and sample data.

For your convenience, we offer bundles which provide the probeware for the activities in the manual. For more, please see:
Computer-based Physics Lab Manual and Bundles
Xplorer GLX-based Physics Lab Manual and Bundles