Review: Density sink or float

What is density?

Density is mass divided by volume. It's measured in grams per cubic centimeter (g/cm³).

How to calculate density?

Density ($\displaystyle ho$) = Mass (m) / Volume (V). Example: $\displaystyle ho = \\frac{5 ext{g}}{2 ext{cm}^3} = 2.5 ext{g/cm}^3$.

True or false: Density affects buoyancy.

True, because objects with lower density than the liquid will float.

What happens to a rubber duck in water?

It floats because its density is less than that of water.

Difference between sink and float.

Sink means an object is denser than the liquid. Float means it's less dense.

Which object sinks: a pebble or a feather?

Pebble sinks. It has a higher density than water.

Fill the blank: Water has a density of ____ g/cm³.

1 g/cm³ at 4°C (39°F).

What is buoyancy?

Buoyancy is the upward force a fluid exerts on an object. It helps objects float.

True or false: All metals sink in water.

False, because some metals like lithium have lower density than water.

What determines if an object floats?

An object floats if its density is less than the liquid's density.

Example of a floating object.

A cork floats because its density is less than water.

How does temperature affect density?

Generally, warmer liquids are less dense and can cause objects to float.