Oil floats on water because

• A. It has a higher boiling point than water
• B. It has a greater viscosity than water
• C. Its density is greater than water
• D. Its specific gravity is less than water

Answer: (D)

Buoyancy is determined by how dense a substance is compared with the surrounding fluid. If something is less dense than water, it will float because the water it displaces weighs more than the substance itself, producing an upward buoyant force that carries it to the surface. Oil has a density lower than water, so its specific gravity is less than water. This makes oil buoyant in water and causes it to float.

The other ideas don’t determine floatation. A higher boiling point doesn’t affect whether something sinks or floats, since it’s about phase change temperature rather than density. Viscosity describes how thick or runny a liquid is, which affects flow, not whether it will float. If oil had a density greater than water, it would sink instead of float.