Density

A lesson on integrity and science

Density is….

A periodic property

How did Mendeleev know there was a missing element?

He calculated the densities and they increased down a family

So Remember:

Density: mass per unit volume

A measure of how compact molecules are in a substance.

Determines whether an object will sink or float in a fluid.

Archimedes Principle

There is a relationship between an object being able to float

(or buoyancy )

and the mass of the fluid that was displaced.

 

This box is filled with water

The object displaces some of the water

The amount of the fluid displaced depends on the density of the object

versus the density of the fluid.

How to find the volume of an irregular shaped object

Measure a known amount of water in a graduated cylinder

Place the object in the waterThen find the volume of water it

displaces in a graduated cylinder, by subtracting the initial volume from the final volume

Divide mass by volume

Solid Liquid Gas

For example: Density of water is 1 g/ml.

Wood has a density of 0.6 g/ml;

Therefore, wood floats in water.

Formula for Density

Density = mass / volume

or

D = m/v.

Density = mass/volume

Volume = mass /density

Mass = density X volume

m

vD

So now, let’s calculate the density for the Coke and Diet Coke.

1. Mass the Coke on the balance.

2. Then divide it by the volume

(ml on the can)

3. Your final answer will be the density.

When you write density, the unit you use is

(the number) g/ml

For example: 3.4 g/ml