This lesson is being recorded

1.

Recording Notice
This lesson is
being recorded

3.

Explore 1: Density
Materials – Viscosity

4.

Objective
Explore the effect of density in various scenarios.

5.

Golden Link Remember this from Resistivity?
Is lead heavy?
A. Yes
B. No
• No, it has a high density.
• An individual lead object may or
may not be heavy.
SLIDE:
5

Golden Link
Calculate the masses of these 4 objects.
Light lead object
Material
Name
Object (kg)
Density (kgm-3)
Lead
1 × 10-9 m3
(1 mm3 )
11,340.0 0.000 011 340
Air
1.3 0.000 000 001 3
1 × 109 m3
(1 km3 )
11,340,000,000,000
1,300,000,000
The calculations show that the
following exist:
• light high-density objects
• heavy low-density objects
SLIDE:
6
Heavy air ‘object’

7.

Lifting a Tree
high mass (heavy) object
low mass (light) object
1 cm
low density material (balsa)
high density material
density, rho ρ = mass / volume = 8 kg / 4 m 3 = 2 kg/m 3
SLIDE:
7

8.

Leaking Tower
Which will travel furthest horizontally? Choose, then watch video.
A
B
C
Answer: C
Pressure demo water column
2:30 min
SLIDE:
8
Because it has the highest pressure.

9.

Duck vs Anvil in Water
Why does the duck float
and the anvil sink?
• The duck is less dense than the water.
• The anvil is more dense than the water.
• The duck happens to be lighter than
the anvil but that is not relevant to the
answer.
SLIDE:
9

10.

Density Effect?
• Try the different
shaped bodies of fluid.
• Also, adjust density to
see what happens.
SLIDE:
10

11.

Density Effect?
Does the density of the fluid effect
the height of the block?
Yes
weight
weight
ρ
SLIDE:
11
ρ

12.

Plimsoll Lines
Plimsoll lines on ship indicate maximum safe loading depth depend on
temperature and salinity.
SLIDE:
12

13.

Density and Temperature
2,562 oC
1,085 oC
Density =
Mass
Volume
0 oC
- 273 oC
• Higher temperature means faster particle movement.
• This means more space is occupied – greater volume.
SLIDE:
13
• Mass is unchanged, so density decreases.

14.

Journey
Water type:
Density:
Supportive:
Safe:
SLIDE:
14
Cold, salty
High
Very
Yes
Water type:
Density:
Supportive:
Safe:
Warm, fresh
Low
Somewhat
Still yes

15.

Plenary: Density Calculation
3.5 tons of a substance are poured into a
container of volume 7.2 m3
Calculate the density change when the
volume expands to 9.4 m3
density =
I
m = 3.5t
V = 7.2 m3
ρ=?
M
3.5t = 3,500 kg
F
m= ρ× V
A
ρ=m / V
S
ρ = 3,500
/ 7.2
ρ = 3,500
/ 9.4
T
ρ = 486.1 kg/m3
ρ = 372.3
kg/m3
SLIDE:
Δρ = 113.8 kgm-3
15
mass
volume
and 9.4 m3
density
=
mass
volume

16.

Explore 2: Explore Activity
Materials – Viscosity

17.

Objective
Apply viscosity ideas in an exam context
SLIDE:
17

18.

Starter
Elephant have tree-like legs, ants have very thin
legs compared to their bodies.
How does the idea in the learn plenary help
explain this?
• When length doubles, bone cross-sectional
area quadruples but mass increases by a
factor of 8.
• Therefore elephants need column-like legs
ants can have spindly ones.
SLIDE:
18

19.

Complete Canvas Activity
SLIDE:
19

20.

Plenary - Pictionary
SLIDE:
20

21.

Explore 3: Practical
Materials – Viscosity

22.

Objective
Apply Viscosity ideas in practical context
SLIDE:
22

23.

Starter
What is the reading on this micrometer?
• 18.6 mm
• 18 + 0.5 + 0.1
SLIDE:
23

24.

Olive Oil: Find Viscosity
Experiment 1
Variable
Detail
Change
Ball size
Measure
Drop speed
Keep constant
Ball material
Fluid: Olive Oil
Experiment 2
SLIDE:
24
Variable
Detail
Change
Ball material
Measure
Drop speed
Keep constant
Fluid: Olive Oil
Ball size