Transcript Using visualiztions of the science of climate change to

Using visualiztions of the science
of climate change to
change the climate of Science
Teaching
CCTCA – February 2014
Brian Martin
The King’s Centre for Visualization in
Science
The King’s University College
Contexts for Good Science Teaching
• Good science teaching provides conceptual hooks
that connect a student’s lived world with the world
of scientific ideas
• Climate Change Science is a complex subject that
reaches into virtually every part of the science
curriculum – this is a natural and fruitful area in
which to create these “hooks”
• Climate Change represents one of humanities
greatest challenges and developing climate change
literacy in students and the general population is a
critical need
Digital Resources at The King’s
Centre for Visualization in Science
vc3chem.ca
www.kcvs.ca
www.explainingclimatechange.ca
Sample “Lessons”
Idea
Concept(s)
Suggested Curricular Links
What is the thickness and mass of
the atmosphere
Force, Pressure, mol, “Back-of-the –
envelope or Fermi questions”
Science 10
Phys 20 – Unit B
Chem 20 – Unit B
How does the burning of CO2 change
the atmosphere?
Stoichiometry
Chem 20 – Unit D
When will the summer polar-cap
disappear?
Slope, equation of line
Science 10. Unit B, D
Physics 20 – Unit A
How do greenhouse gases “work”?
Light and Matter Interaction,
Blackbody radiation, quantum
Phys 30 – Unit C,D
Acidification of the Oceans
Solutions, PH
Chem 30 – Unit D
The Physics of Wind Power
Mitigation, Conservation of
Momentum and Energy, Power
Chem 20 – Unit C
Phys 30 – Unit A
Photovoltaic Energy
Mitigation, Energy and Power,
dimensional arguments
Science 10
Phys 20 – Unit C
(1) Mass of the Atmosphere
Basic Facts:
•Atmospheric pressure 100 kPa
•1 Pa = 1N/m2
•Radius of Earth 6.38 X 106m
Every square m of the Earth’s
surface supports 104 kg of air
SA  4 R 2
What is the mass
of a column of air
1m2 at the base
which exerts a
force of 100 kN ?
Mass  4 R 2 (104 kg / m 2 )
 4 (6.38  106 m )2 (10 4 kg / m 2 )
 5  1018 kg
Ans: mg = 100 000 N
m = 104 kg
How many molecules are there in the
atmosphere?
Basic Facts:
•Atmospheric is mostly N2 and O2
•“molar mass” approximately 30
g/mol
•Mass of atmosphere 5 X 1018 kg
Number of mols 
mass of atmosphere
molar mass
5  1021 g

 1.7  1020 mol
30 g / mol
(2) How Much CO2 in ppm Does a
Barrel of Oil Produce? Basic Facts:
1 barrel releases 425 kg of CO2; in moles this is
425 kg
 104 mol
0.044 kg / mol
•Carbon-based fuel releases 3.15
times its mass in CO2
•Mass of a barrel of oil is about
135 kg or
•1 barrel releases 425 kg CO2
•CO2 has a molar mass of 44g/mol
Since the atmosphere contains 1.7 X 1020 mol
one barrel will release
104
17

6

10
1.7  1020
This is the fraction of CO2 relative to the entire atmosphere – multiply by 1
million to get the parts-per-million or ppm. So, 1 barrel releases an additional
6  1011 ppm
Is the observed increase in CO2 “natural” or
Basic Facts:
…
(30  109 bbl/a)(6  1011 ppm/bbl )
 1.8 ppm/a
•1 barrel of oil releases 6 X 10-11
ppm of new CO2 into the
atmosphere
•30 billion barrels of oil are
consumed annually
Slope = 1.8 pm/a
46 ppm
25a
Basic Facts:
A Bit Closer to home…
what is the annual Carbon footprint of the
Alberta Oil Sands in ppm?

•Fort Mac produces 1.5 million
barrels of oil per day
•Annual Carbon footprint is 40
million tonnes of carbon dioxide
•1 barrel of oil releases 6 X 10-11
ppm of new CO2 into the
atmosphere
40 Mt CO2
 9.4  107 bbl
425 kg / bbl
(9.4  107 bbl/a)(6  1011 ppm/bbl )
 0.006 ppm/a
…but – that’s not the end of the story!
Components of Fossil Fuel Emissions
Le Quéré et al. 2009, Nature Geoscience
How about Coal-Generated Power?
Basic Facts:
•The Sundance Coal-fired Power
Generation Plant on Lake
Wabamum produces 2126 MW
•Annual Carbon footprint is 17.5
million tonnes of carbon dioxide
The Sundance plant produces roughly 17.5/40 times as much CO2
as The Alberta Oil Sands
In other words – Sundance adds
(17.5 / 40)(0.006 ppm/a)= 0.003 ppm/a
(or about “half-a-Fort Mac”)
Let’s Re-run the Numbers…
Basic Facts:
•CO2 sources by percent:
•Coal 40%
•Oil 36%
•Natural Gas 20%
•Other 4%
If the burning of oil accounts for only 36% of
the total CO2 loading then the total
(anthropogenic) loading is …
1.8 ppm / a
 5 ppm / a
0.36
So – where is the rest going?
The Melting Polar Cap
If current trends continue
when will September
Polar Sea-ice disappear?
Area (Mkm2)
7.2
7.55
7.02
7.2
6.03
5.81
5.45
Polar Sea-Ice
9
8
Area (million km2)
Year
0
5
10
15
20
25
30
7
6
5
y = -0.0694x + 7.65
4
3
2
1
0
0
5
10
15
20
Years (since 1979)
25
30
35
How Do Greenhouse Gases Work?
(3) Ocean Acidification
• The ocean buffers atmospheric
CO2
• The ocean’s pH has dropped from
8.20 to about 8.05 since the
industrial revolution
D pH is only 0.15 – why Worry?

pH   log10[H3O ]
so

(  pH )
[H3O ]  10
• At [8.20] H3O+ concentration is 6.31 × 10-9 mol L-1
• At [8.05] H3O+ concentration is 8.91 × 10-9 mol L-1
• This represents a 41% increase in hydronium
ions – the ocean is being acidified
(4) The Physics of Wind Power
• How much power can a 100 m
diameter windmill produce?
• Estimate the size of a wind farm
capable of producing the power
output of the Sundance
thermoelectric plant (2100 MW)
Energy from the wind
• A packet of air of mass ‘m’ moving
with velocity ‘v’ has energy given
as
1
Ek  mv 2
2
m   Av Dt   A1v1Dt   A2v2Dt
1
Ek   Av Dtv 2
2
1
P   Av 3   Av 2Dv
2
Energy and power
scale with the CUBE
of wind velocity!
The total energy available is the
difference between the energy of the
incident air packet and the exiting air
packet – Power that can be extracted is
expressed as:
Peffective
1
 P   Av(v12  v22 )
2
Note the crucial role of the incident and exit wind
velocity – we want to find the “sweet spot” – what is the
maximum value for Peffective?
Force and Power on a Windmill
• A variation on Newton’s 2nd Law
Dv
m
F  ma  m

Dv
Dt
Dt
 Av Dt
F 
Dv   Av Dv
Dt
P  Fv   Av 2Dv
• Combine the two differently derived
expressions for P
1
 Av(v12  v22 )   Av 2 Dv
2
1 2
(v1  v22 )  v Dv  v(v1  v2 )
2
This is known as Betz’s Law (circa 1920) and
leads to a remarkable result – the velocity
across the rotor of the windmill is
(v1  v2 )
v
2
Insert this into the power equation to get…
(v1  v2 ) 2
1
P  A
(v1  v22 )
2
2
Let x = v1/v2 to get…
1
3
2
P   Av1 (1  x)(1  x )
4
1
1
1
3
P   Av1 (1  )(1  )
4
3
9
16 1

(  Av13 ) or
27 2
1
3
 C p  Av1
2
Cp is the power coefficient for a wind turbine and the
ratio 16/27 = 0.59 represents the maximum possible power
that can be extracted. More typically wind turbines achieve
80% of this or 0.47
Example – Enercon101 Wind Generator
Optimal wind speed is
around 10 m/s
Cp = 0.47 so
1
(0.48)(1.2kg/m3 ) (50m)2(10m/s)3
2
 2400 kW
P 
How Many?
• To produce 2100 MW you will need…
n
2100 MW
 875 units
2.4 MW/unit
• “Rule of thumb” – generator spacing is 7 times the diameter
of the rotor or (0.1km)(7) = 0.7km
• Place in a grid 30 units X 30 units = 21 km X 21 km
• Cost? A 2008 figure commonly used is 1.3 million/MW so a
2100 MW wind farm would cost approximately $275 million
• From the TransAlta web site… “A 53-megawatt uprate to
Sundance 5 was completed in 2009 at a cost of $75 million.”
(5) Photovoltaic Energy
• By how much can I hope to
reduce my annual CO2 footprint
if I install 12, 235 W solar panels
on the roof of my house?
• How does the cost of electricity
produced by a PV panel
compare with current costs
@12 c/kWh?
kW = 1000 W is a power unit
kWh = 1000 W × 3600 s = 3.6 MJ
which is an energy unit
My Annual Electricity Use
• Total electrical energy
consumption 2011 was 10 MWh
• Under bright sunlight each panel
averages 140 W (averaged over
the year)
• Edmonton receives on average
2300 h bright sunshine per year
E  (12 panels)(140 W )(2300 h)
 3.86 MWh
I can offset about 40% of
my (electrical) CO2
footprint
Cost of Solar Energy
• Total cash outlay for system =
$15000
• Warranty period = 25 years;
estimated lifetime > 40 years
• Assume an average annual
energy production of 3.6 MWh
Net Cost  ($15000/25 a)  $600a-1
so...
$600a-1
 17 c/kWh
-1
3600 kWh a
But the cost of
sunlight won’t go up!
And there are a lot more…
•
•
•
•
•
•
•
•
•
Compare CO2 footprints of Methane and Coal
Look at Isotopic Mass Ratios and Ice-cores
Nuclear energy (conventional, fast breeder, Thorium)
Bio-fuels
Look at Carbonate-biCarbonate speciation
Greenhouse gas heating through collisional de-excitation
Declining sea ice and slope
IR spectroscopy and spectral windows
etc
Resources…
• www.kcvs.ca
• www.explainingclimatechange.ca
• Using Climate Change to Creat Rich Contexts for
Physics and Chemistry Education. Brian Martin and Peter
Mahaffy
Thank You!