1. DENSITY

2. Density is the measure of mass per unit volume of substance. So, density is a measure of the amount of matter (particles) in a given volume (space) of a substance. Density can be explained using the particle theory of matter.

3. DENSITY AND PARTICLE THEORY The Particle theory of matter can help explain density, since density depends on two things: 1.The mass of the particles 2. How tightly the particles are “packed” (volume).

4. Particles of a solid are usually more closely packed than particles in a liquid, which are more closely packed than particles of a gas. Therefore, solids are generally denser than liquids, which are denser than gases.

5. Density is also affected by the type of particles a substance is made of. Different substances have different densities Even though oil and water are both liquids, water is much denser. Helium is much less dense than air, even though they are both gases.

6. CALCULATING DENSITY: Density is a ratio that compares the mass to the volume. Density is determined by the following equation: density = mass/volume The common units of measurement for density of solids and liquids are g/mL^3 or g/cm^3, and for gases kg/m^3