2.4 Density _ 2

• Natuurkunde / Scheikunde
• Middelbare school
• havo
• Leerjaar 2

Planning

• Homework

• Revision previous lessons

• Explanation 2.4

• Let's work

Homework

Any questions?

You determine the mass with a ...

1. ruler
2. protractor
3. scale
4. measuring cilinder

149.56 g = ... kg

1. 149.256 kg
2. 1.49256 kg
3. 142.56 kg
4. 0.149256 kg

How do you determine the Volume of an object?

The formula for calculating the volume of a cylindrical object is:

1. V=π⋅2r⋅h
2. V=π⋅d​2​​⋅h
3. V=π⋅r​2​​⋅h
4. V=π⋅(r⋅r)⋅h

Here you see the immersion method, where the volume of a stone is determined.
What is the Volume of this stone?

1. 24cm​3​​
2. 15cm​3​​
3. 9cm​3​​
4. 39cm​3​​

45 dm³ = ... L

1. 4.5L
2. 45L
3. 450L
4. 45000L

Explanation

Density

= property ...

= is a physical and chemical quantity (variable) that expresses how much mass of that substance is present in a given volume.

The mass (in grams) of 1 cm³ of a substance.

Every substance with a volume of 1 cm³  has a different mass...

Explanation

Aluminum

Density of 2,70 g/cm³ 

You pronounce this as: 2.70 grams per cubic centimeter.

If you take 1 cm³ aluminum and place it on a scale, the scale will indicate 2.70 grams

Explanation

Caltculate the Density:

Explanation

Caltculate the Density:

Explanation

Caltculate the Density:

ρ=​V​​m​​

Explanation

Caltculate the Density:

ρ=​V​​m​​

Variable	Symb.	Unit	Symb.
Density	(rho)	gram per cubic centimeter	g/
Mass	m	gram	g
Volume	V	cubic centimeter

ρ

cm​3​​

cm​3​​

What will happen when you put a brick into water?

1. It sinks
2. It hovers
3. It floats

What will happen when you put 'normal' wood into water?

1. It sinks
2. It hovers
3. It floats

Why does a brick sink and wood float?

Explanation

Sinking / Hovering / Floating:

• Sinking: The substance that sinks has a bigger density 

• Hovers: The density of the substances are equal.
  

• Floating: The substance that floats has a smaller density 

Explanation

Density of water = 1 g/cm³

If density   > 1 g/cm3 --> It sinks

If density = 1 g/cm3 --> It hovers

If density   < 1 g/cm3 --> It floats

Describe in your own
words what density means

Does the mass of an object affects if it sinks, hovers and floats?

1. No
2. Yes

Which liquid has the ...

lowest density

highest density

Let's work

Now: 

- Read  §2.4 

- Make §2.4 - exercise.: 36, 37, 39, 40, 45