Catalyst

1. What is density and why is it important?

2. What kind of jobs require knowledge about density? (HINT: there are a lot of them in Hawai’i!)

CHALLENGEIf I have a can of coke and I put it in a bowl

of water, will it sink or float? What about a can of diet coke?

For notes today…

You’ll need your notebook AND your packet turned to page 2.

Density

Which floats, Coke or diet Coke?

Definition of Density

Density: the amount of matter per unit of space of an object

But what does that really mean?

Compare Thing 1 and Thing 2

Thing 1 Thing 2

Which of these has more matter? Which has more space?So which one is the most dense?

Compare Thing 1 and Thing 2

Thing 1 Thing 2

Matter/ Matter/ Space SpaceLess

dense

More dense

Definition of Density

Density: the amount of matter per unit of space of an object

But what does that really mean?

How compact or packed together the matter is in the space of an object.

Compare Thing 3 and Thing 4

Thing 3 Thing 4

Which of these has more matter? Which has more space?So which one is the most dense?

More dense

Less dense

Apply it to real life:

More sugar Less sugar

What makes Coke different from diet Coke?

So what can we conclude about density?

More dense = sink Less dense = float

Zoom! Video

Liquid Layers – Check it out!

Which liquid has the highest density?

Which liquid has the lowest density?

Which liquid has the middle density?

Can you tell the density of something by looking at it?

Definition of Density

Density: the amount of matter per unit of space of an object

Matter: per: Space:Mass Volume

Formula for Density

D = m = mass = g or g V volume mL cm3

Tools: scaleand ruler/graduatedcylinder

lecturePLUS Timberlake 16

Example 1

Osmium is a very dense metal. What is its density if 50.00 g of the metal occupiesa volume of 2.22 cm3?

lecturePLUS Timberlake 17

Solution

D = mass = 50.00 g = volume2.22 cm3

= 22.522522 g/cm3 = 22.5 g/cm3

lecturePLUS Timberlake 18

Example 2What is the density of 48 g of a metal if the metal raises the level of water in a graduated cylinder from 25 mL to 33 mL?

33 mL 25 mL

lecturePLUS Timberlake 19

Solution Volume (mL) of water displaced

= 33 mL - 25 mL = 8 mL

D = mass = 48 g = volume 8 mL

= 6 g/mL