Density
Densitet
ChemistryCommon
Discovered 250 BC · Archimedes
SPARKON06 / 10
Density
The ideaDensity is how much mass is packed into each bit of volume; the less dense thing floats.
ρ = m / V
Lets you predictWhether something floats before you drop it in.
Tests usually ask
  • Calculate a density
  • Which substance is it?
Scan for the full explanation and a practice question.
SPARKON · 06 / 10
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Chemistry ● Common: a core idea every course needs

Density

Swedish: Densitet · Discovered: Archimedes, about 250 BC

Density is how much mass is packed into each bit of volume; the less dense thing floats.

ρ = m / V

Why it works

Ice is about 0.92 g/cm³ and water is 1.00 g/cm³. Ice is less dense, so it floats with about a tenth above the surface.

Water is strange: most substances are denser as solids, but water molecules hold each other at arm's length when they freeze. That is why lakes freeze from the top and fish survive the winter.

What it lets you predict

Whether something floats before you drop it in.

How tests ask about it

  • Calculate a density
  • Which substance is it?

Try it

A stone has a mass of 50 g and a volume of 20 cm³. Will it float in water?

Show the answer

ρ = 50 / 20 = 2.5 g/cm³, more than water's 1.00, so it sinks.

Connects to

GoldOxygen

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