Fluids
Density

In the last activity, you discovered that no matter
how much substance you used, the mass-to-volume
ratio stayed the same. This ratio is density.
Density – A measure of the
amount of matter (mass) per
unit volume of a substance.

Time for ... Mr. Edwards The Density Song
What is Density?

You can use the particle theory to help explain density:
◦ Particles of a solid are usually more closely packed than particles of a
liquid, which are more closely packed than particles of a gas.
◦ Therefore, solids are generally denser than liquids, which are denser
than gases.

Density is also affected by
the type of particles a
substance is made of.
◦ Oil and water are both liquids,
but water is much denser.
◦ Helium is much less dense than
air.
Density & The Particle Theory

Can you explain the science behind these
experiments/demonstrations? Think of how
density relates to the particle theory.
◦ Floating Egg
◦ HWK: Explain how density affects the results for
each egg. Use a diagram to explain each.
◦ Floating/Sinking Coke?
◦ Underwater Volcano - Density?
◦ Ask yourself, why does this happen?
Density & The Particle Theory

Density is determined by the following equation:
Density

Mass
Volume

The common units of measurement for density of
solids and liquids are g/mL or g/cm , and for gases,
kg/m .

T/P/S: Based on the formula, how would you …
a) Increase density?
b) Decrease density?
c) Real-life examples?
Calculating Density

An empty container has a mass of 50g. When 75mL
of oil are placed in it, the total mass is 120g.
Calculate the density of oil.
Given:
1.
mass of container = 50g
mass of container & oil = 120g
Volume of oil = 75mL
Need to find mass of oil first:
• Mass = 120g – 50g
= 70g
2.
Use the formula to find density:
• Density = mass/volume
= 70g/75mL
= 0.93g/mL
• Therefore, the density of the oil is 0.9g/mL.
Calculating Density
Density of Some Common Materials
1.
Use the particle theory to explain densities
in solids, liquids, and gases.
2.
Calculate the density of a diamond if the
volume of the diamond is 0.50cm and its
mass is 1.75g.
3.
To prep for the upcoming lab, research the
densities of:

Water, Rubbing Alcohol, Maple Syrup, Laundry
Detergent, Vegetable Oil
Homework Questions
Fun with Density!

It’s time for you to try one of the class’ density
demonstrations. Complete each demonstration,
but add an additional test:
◦ Floating Eggs – Test sugar
◦ Underwater Volcano – Cold Water in Hot Water

Make sure you create your own observation table
to record your data. Think qualitative and
quantitative data.

Introduction: Seven Layer Density

Lab Prep:
◦ Read over lab handout
◦ Complete a hypothesis &
variables
◦ Create the necessary tables for
observations
Science Lab: Layer Liquid
Fluid
Density
Observations
Water
Rubbing
Alcohol
Maple
Syrup
Laundry
Detergent
Vegetable
Oil
Lab Chart Example - Liquids
Fluid/
Object
Observations
Density
(Description)
Air Bubble
Wooden
Bead
Plastic Gem
Bolt
Popcorn
Kernel
Lab Chart Example – Gas & Solids