Buoyancy Experiment Calculator

Buoyancy Experiment

A classic buoyancy experiment compares the upward buoyant force on a fully submerged object to its weight. Enter fluid density, object mass, and object volume to predict whether the object floats, sinks, or achieves neutral buoyancy.

Buoyancy Formulas

$$F_b = \rho_{\text{fluid}} V g$$ $$W = m g$$

If $F_b > W$ the object floats, if $F_b < W$ it sinks, and if they are equal the object is neutrally buoyant. Fresh water has density about 1000 kg/m³ and $g \approx 9.81$ m/s².

Example: a 0.5 kg object with volume 0.0006 m³ in water gives $F_b = 1000 \times 0.0006 \times 9.81 = 5.89$ N and $W = 4.91$ N, so the object floats.

Frequently Asked Questions

What inputs does the buoyancy experiment need?

Fluid density (kg/m³), object mass (kg), and object volume (m³). The calculator assumes the object is fully submerged so displaced volume equals object volume.

How do I know if an object will float?

Compare buoyant force to weight. If buoyant force exceeds weight, the object floats. If weight is greater, it sinks. Equal forces mean neutral buoyancy.

What fluid density should I use for water?

Use 1000 kg/m³ for fresh water at room temperature. Seawater is about 1025 kg/m³ and provides slightly more buoyant force.

What is neutral buoyancy?

Neutral buoyancy occurs when buoyant force equals object weight. The object neither rises nor sinks, similar to a diver hovering at a fixed depth.

Does this work for irregular shapes?

Yes, as long as you know the object's total volume. Shape does not matter for buoyant force—only the volume of fluid displaced.

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