Transcript chapter01post

Physics 1001
Energy and the Environment
Spring 2016 1:25 MWF 20 West Bank Skyway
Instructor: J. Woods Halley (email: woods @ woods1.spa.umn.edu)
Course web page:
http://www.physics.umn.edu/courses/2016/spring
First day:
Review Syllabus
Poll for background and interests and practise
using 'clickers'
Review some dimensions of the social and
economic energy problem
Some practise with reading graphs and units
Using Iclickers:
Wait until the little iclicker box appears in the
upper left hand corner of the screen at the front of the
room.
Then turn your iclicker on. You should see
'Physics 1001'
and then 'Ready' on your clicker screen.
Wait until I start the countdown for a question.
Press a button to record your answer during the
countdown.
When your answer is received you should see a check
mark.
When the clock stops you will see 'Ready' again
If, by accident, you press an answer at the wrong time
it will say 'closed' but you can still answer when the
clock starts.
Registration (just once)
After you have answered at least one question in class
go to
http://www1.iclicker.com/register-clicker-remote
to register your clicker device. You will need to
have your clicker and your student ID number with you
to do this.
:
2014-2015 will be which year of
college for you?
A. first
B. second
C. third
D. fourth
E. more than fourth
In what college of the university is
your major?
A. CLA
B. CBS
C. IT
D. CAFNR
E. other
What is the most important reason
that you are taking this course?
A. It fulfills a graduation requirement.
B. I will need to have some familiarity with
the subject in my career.
C. I’m concerned about the social impacts of
human energy and environmental policies
and actions
D. something else.
What was the last time you used
algebra in a course or
professionally?
A.. last fall
B. last spring
C. within the last 3 years
D. longer ago than these
A few administrative clarifications:
Permissions: If there are openings
in a lab session to which you want
to switch, go to the session and ask
the TA if there is room. If there is,
give him your name and he will contact
me to help arrange the switch.
Registration in the whole
course is limited to 136 people
because of available lab space.
If registration drops below that level
then new registrants can register on
line. No permission numbers will be
given for registration over the 136 limit.
Where we are going:
We will follow the paths that energy takes as
twenty first society transforms and uses it.
Along the way we will study
the physical processes that take place
and
the physics principles that control them
and
the social, political and environmental
consequences
Where we are going:
We will follow the paths that energy takes as
twenty first society transforms and uses it.
Along the way we will study
the physical processes that take place
and
the physics principles that control them
and
the social, political and environmental
consequences
There is another version of this flow chart in
your book (Figure 1.13).
We will study the meaning of the units ('Quads')
later. For now, just think of them as a way
of measuring quantities of energy.
Some things to note about the flow chart:
Let's compare the energy coming in from the
left in the flow chart to the amount of
energy going out at the right.
The amount of
energy coming in
from the left is
0.11
8.35
A. much larger
2.68
0.70
0.37
23.37
19.76
3.88
35.27
B. much smaller
54.64
C. somewhat smaller
D. somewhat larger
E. The same to
within 0.1 quad
as the amount going
out on the right.
39.97
Exactly the same amount of energy
.comes in and goes out.
NO ENERGY IS EVER DESTROYED OR CREATED.
That is the (physics) meaning of the
law of conservation of energy. (Chapter 3)
WARNING: The words 'conserved'
and 'conservation' are used with three
distinct meanings in public discussions
of energy and its use. In the sentence
above I use the word 'conservation'
as it is used in physics to describe
energy. I return to this next week.
Another thing about the chart:
Look over at the right:
The gray box says 'Rejected energy'. That's
energy that wasn't used usefully by humans.
The black box says 'Energy services'. That's
energy that was useful for humans.
Another thing about the chart:
Look over at the right:
The gray box says 'Rejected energy'. That's
energy that wasn't used usefully by humans.
The black box says 'Energy services'. That's
energy that was useful for humans.
54.64
What per cent of the energy
used per year in the US is
'Rejected'?
A. 39.97/(39.97+54.64)=42%
B. 39.97/54.64=73%
C. 54.64/(39.97+54.64)=58%
D.54.64/39.97=136%
E.Can't tell from graph
39.97
THERE IS MORE REJECTED ENERGY THAN
ENERGY SERVICES.
The whole system is wasting a lot of the energy.
We will learn that to a certain extent that is
UNAVOIDABLE due to something called
the second law of thermodynamics.(Chapter 4)
Next, look at the left hand side of the chart.
There you see the 'inputs' into our energy
system. That is, where the energy comes from.
Petroleum, Natural
Gas and Coal are called 'fossil fuels' (Chapter 7)
because they originate from plant and animal life
that was buried millions of years ago.
The fossil fuels have been used as
primary sources by industrial society for more than
a century.
0.11
solar
8.35
nuclear
2.68
hydro
wind
0.70
,What fraction of the input
energy is 'fossil fuels'?
A. 83%
0.37 geothermal
23.37
B. 87%
natural gas
h
19.76
C 58%.
coal
D. 46%
3.88
biomass
petroleum
35.27
Total 94.6 quads
More than 3/4 of the energy inputs
to our system come from fossil fuels.
Problems with fossil fuels which we will discuss:
They are a finite resource and will run out.
and
Their use produces large amounts of carbon
dioxide in the air leading to climate change
by a mechanism we will study, as well as
other environmental problems.
Let's take a preliminary look at some data
which illustrates these points.
----- Hubert's
prediction
___ actual
US oil
production
----- Hubert's
prediction
___ actual
US oil
production
Various predictions
for world oil
production
Natural Gas
US production
Figure 1-20 p20
Natural Gas
US production
Figure 1-20 p20
Coal US production
Summary:
The Hubbert model correctly predicted in 1956
that US oil production would peak in 1971
Currently applying the same model to WORLD oil
production predicts that it
will, or already has, peaked within 1 to 10
years of the present.
Coal and gas are predicted to run out later,
but within the next century.
Now let's have a look at the other problem
with fossil fuels: They produce a lot
of carbon dioxide leading to climate change.
There are really two statements here,
separately illustrated by the data in the
next two slides.
The carbon dioxide is definitely increasing in the air:
And the average surface temperature of the earth's
surface is rising.
We will study the mechanism by which these
two phenomena are believed to be
connected. (Chapter 9)
I will return to the flow chart often during the
course to point out how the various topics
we will study are all chosen in order to
understand aspects of those flows.
Now we will take a few minutes to deal with
a technical point which cannot be avoided
if you wish to think clearly and quantitatively
about energy issues:
The energy in the flow chart was expressed
in 'quads (per year)' but many other units
are used for energy for historical reasons
but they all refer to energy. We often need to
convert from one form of units to another.
Some practise with units:
To make sense of the data on energy
which you might see on your electrical
bill, in the text or in an article in the
newspaper or on the web, you will
need to be able to convert from one
kind of energy unit to another.
To do this, you can use the tables in
Appendix B of your book.
About how much energy from petroleum
was used in 2000 in quadrillions of btu per year?
A.20 qbtu/yr B. 40 qbtu/yr C,.7300 qbtu/yr
D. can’t tell from this graph
Fig. 1-7, p. 11
It matters because about 40% of
our energy comes from petroleum and the
supply is about to start shrinking as the
demand, particularly from India and China,
Is growing fast.
The supply of natural gas is also predicted
to peak somewhat later while the supply of
coal will last much longer (about a century).
But the use of coal imposes serious environmental
risks.
Environmental Issues
We will discuss several environmental issues
associated with human energy conversion and
use. These include the production of
particulates (dirt) in the emissions from coal
burning electrical plants for example. This is
still a problem in the US and a very serious one
elsewhere. However it is more manageable than
greenhouse gas/global warming problem which
is more difficult and far from being under control
anywhere In the world.
The rising amounts of carbon dioxide lead,
In ways we will discuss, to the rise in
average temperature, which in turn is
leading to climate change. The basic
mechanisms are well understood but
the climate system is complex and it is
not possible to model all the details with
complete certainty. There is growing scientific
consensus that there is a causal connection
between the human burning of fossil fuels to
get energy, the rising average atmospheric
temperature and the manifestations of climate
change including more violent weather, melting
ice caps, droughts and floods.
Summary
The course theme will be methods of
human energy conversion and its environmental
consequences
You will learn or review basic physics definitions
and principles in order to understand these
issues
Most fundamental is the quantitative definition of
energy and its various forms
Unit conversions are an important skill in discussing
these issues.
Conceptual questions:
What words do you associate with the idea of
energy?
Do you use the word energy in different ways
in different contexts? Which ways and which
contexts?
Same questions for these words:
velocity
acceleration
force
What’s important about energy and the
policies which control its transformation,
distribution and use?
Economic
Environmental