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Fluids · Physics

Buoyancy Simulation

Drop blocks of wood, ice, brick and aluminium into water, oil or honey. Read the weight, buoyant force and apparent weight, and see Archimedes' principle hold every time.

Interactive virtual lab · no download · works on phones and laptops

Chapter
Mechanical Properties of Fluids
For
Class 9 · Class 11 · NEET
Time
~12 min

How to use it

  1. 1Drag a block into the pool, or drop it from the shelf.
  2. 2Change the block's material, mass and volume.
  3. 3Change the fluid and gravity.
  4. 4Turn on force arrows and the scale to read apparent weight.

What to notice

  • Buoyant force = weight of the fluid displaced = ρ_fluid · V_submerged · g.
  • An object floats when its density is less than the fluid's.
  • A floating object sinks until it displaces its own weight.
  • Apparent weight = weight − buoyant force.

For teachers

Teach it in 20 minutes

A lesson plan, questions to put to the class, a quick quiz you can project or print, and the formulas behind Buoyancy.

  1. 1Hook

    ~2 min
    • Ask: “A tonne of steel sinks, so how does a steel ship float?” Then drop blocks of different materials into water.

  2. 2Demonstrate

    ~7 min
    • Drag a block into the pool, or drop it from the shelf.
    • Change the block's material, mass and volume.
    • Change the fluid and gravity.
    • Turn on force arrows and the scale to read apparent weight.

  3. 3Pause and ask

    ~5 min
    • Have a student say this in their own words: Buoyant force = weight of the fluid displaced = ρ_fluid · V_submerged · g.
    • Have a student say this in their own words: An object floats when its density is less than the fluid's.
    • Have a student say this in their own words: A floating object sinks until it displaces its own weight.
    • Have a student say this in their own words: Apparent weight = weight − buoyant force.

  4. 4Check

    ~6 min
    • Run the 6-question quiz below: project it and take answers by show of fingers (1–4), or print it as a worksheet.

About the Buoyancy simulation

Any object in a fluid is pushed up by a buoyant force equal to the weight of the fluid it displaces — Archimedes' principle. If that upthrust can match the object's weight before it is fully submerged, the object floats; otherwise it sinks.

In this buoyancy simulation you drop blocks of different materials into fluids such as water, oil and honey, read the weight and the buoyant force on spring scales, and see how much of a floating block sits under the surface. It covers Floatation in Class 9 and Mechanical Properties of Fluids in Class 11 and NEET.

Also covers: archimedes principle, floating, sinking, upthrust, apparent weight, boat.

Frequently asked questions

Why does a steel ship float when a steel bolt sinks?

The ship's hollow shape displaces a huge volume of water, so its average density is less than water's. The bolt's volume is tiny for its weight.

Does the buoyant force depend on the object's weight?

No — only on the volume submerged and the fluid's density. Weight decides whether that force is enough to float.

Why do things float higher in seawater?

Seawater is denser, so less volume needs to be submerged to displace the object's weight.

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