Density
Density ρ is mass per unit volume: ρ = m/V. It helps explain floating and sinking and is central to buoyancy.
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Definition of density
Density (ρ) is defined as mass per unit volume: ρ = m/V. Objects with high mass packed into a small volume have high density; those with the same mass spread over a larger volume have lower density.
✔ Key takeaway: ρ = m/V: how much mass is packed into a given volume.
Floating and sinking
An object floats in a fluid if its average density is less than that of the fluid. If its density is greater, it sinks. Large ships float because their hull encloses air, so the overall density (ship + air) is less than the density of water.
✔ Key takeaway: Floating depends on relative densities, not just on mass or size.
Link to simulator: Adjust object mass and volume and compare with fluid density in the density simulator.
💭 Think about this:
How can a huge metal ship float while a small solid metal ball sinks?