The Particle Model can explain Density and the three states of matter

Density is a measure of the compactness of a substance. It related the mass of a substance to how much space it takes up

• Density(kg/m3) = mass(kg) / volume(m3)

• The density of an object depends on what it is made of and how its particles are arranged

• A dense material has its particles packed tightly together. The particles in a less dense material are more spread out-if you compressed the material, its particles would move closer together, and it would become more dense

The three states of matter are solid, liquid and gas

Solids-strong forces of attraction hold the particles close together in a fixed, regular arrangement. The particles don’t have much energy so they can only vibrate about their fixed positions. The density is generally highest in this state as the particles are closest together

Liquids-there are weaker forces of attraction between the particles. The particles are close together, but can move past each other, and form irregular arrangements, They have more energy than the particles in a solid, and less dense than solids

Gases-there are almost no forces of attraction between the particles. Particles have more energy than in liquids and gases-they’re free to move and at higher speeds. Generally less dense

Need to measure density in different ways

Density of solid object

• Use a balance to measure its mass

• If it’s a regular solid, start by measuring its length, width and height with a piece of equipment(ruler). Then calculate volume using relevant formula for the shape

• For an irregular object, you can find volume by submerging it in a eureka can filled with water. The water displaced will be transferred into a measuring cylinder

• Record the volume of water in measuring cylinder

• Plug the objects mass and volume into formula to find its density

Density of a liquid:

• Place a measuring cylinder on a balance and zero the balance

• Pour 10ml of the liquid into the measuring cylinder and record the liquids mass

• Pour another 10ml into the measuring cylinder , repeating the process until the cylinder is full and recording the total volume and mass each time

• For each measurement , use the formula to find the density

• Finally, take an average of your calculated densities. This gives you a value for the density of the liquid.