Density and Buoyancy
Density is the amount of mass contained in a known volume.
- Same mass + Less space = more density
- more mass + same space = more density
Density = Mass/Volume
Sink or Float?
Buoyancy: how well an object floats, usually in water but not necessarily.
Dish soap (1.06 g/mL) — sink
Milk (1.03 g/mL) — sink
Vegetable oil (0.91g/mL) — float
Rubbing Alcohol (0.786g/mL) — float
Corn Syrup (1.33 g/mL) — sink
Honey (1.38g/mL) — sink
Solids are denser than liquids because there is more mass per volume in a solid. The molecules are closer together in a solid. Solids have less heat. When temperature increases molecules move faster and farther apart and become less dense. This is called thermal expansion. When a substance becomes colder or its temperature decreases, the molecules move slower, stay closer together, and get more dense. This is called thermal contraction. However this is not the case with water. In water the hydrogens form a loose hydrogen bond with the oxygen of other molecules, and this keep the molecules apart, even when they become colder or lose energy. They form a less dense lattice structure.
