Science Fair Projects World

Density and Buoyancy of Liquids


Investigate the density and buoyancy of different liquid solutions.


  • Graduated cylinder
  • Water
  • Sugar
  • Salt
  • Vegetable oil
  • Food coloring (optional)
  • Hydrometer or mass balance
  • Notebook for observations


  1. Measure a specific volume of water in the graduated cylinder and record its mass or density using a hydrometer.
  2. Add sugar incrementally to the water, stirring after each addition until it completely dissolves.
  3. Record the change in mass or density after each addition.
  4. Repeat the procedure with a salt solution.
  5. Measure the density of vegetable oil and compare it to water by carefully layering them in the graduated cylinder. Optional: Add food coloring for visual effect.
  6. Observe and record the buoyancy of each liquid solution.
  7. Analyze the results to understand the principles of density and buoyancy in liquids.