Science 24 Tutorial – Nov. 4th, 2003-11-02
Go over what assignments are due this week. Unit 2 Test on Friday!
In U2L9, you will learn all about fossil fuels.
How are fossil fuels formed? (Refer to figure 8.1 on page 136 and ask “how do you think
the fish outline on page 136 could have been imprinted in stone?”) Discuss.
Ans. Remains of ancient swamp vegetation got covered by layers of sediment. This
created heat and pressure changing the organic matter into coal, oil and natural gas.
(Refer to page 136 in text).
Read points A-D at bottom of page 136. Organic matter was covered by layers of
sediment. There was no oxygen in these layers, so the plant material could not
decompose.Time and increased pressure make coal harder and harder, and remove the
water.
Pg. 137 – Reading Check (Have each student contribute a point).
1. About 300 million years ago, plants lived in swampy areas.
2. The plants died and were covered by layers of sediment.
3. Since there was no oxygen under the sediment, plant material did not decompose.
4. Pressure and heat from being buried resulted in lignite coal.
5. Some lignite received more pressure and heat; bituminous coal was formed.
6. Bituminous coal received more pressure and heat, and was changed into anthracite
coal.
Coal is a rock…some people have a hard time envisioning how a rock can burn.
However, coal comes from living plants. Wood from trees is dried and burned for fuel.
Coal is made from similar plants that lived millions of years ago, died, were compressed,
and can now be burned.
Read “Did you Know” on page 137.
Pg. 137 – Reading Check at bottom of the page.
• Coal-fired steam engines provided the power for factories.
• Coal-fired locomotives moved people and goods in trains across the country.
Students might bring up other answers, not from this part of the textbook,
including:
• Coal-burning furnaces were used to heat homes.
• Some kitchen stoves used coal as a source of fuel.
• Coal-burning tractors worked the land and threshed grain.
What are some different ways that coal can be mined?
When coal is near the surface, open-pit techniques are used. Large shovels remove the
overburden. The exposed coal is blasted to break it up and shovelled into large trucks or
haulers.
Underground mining involves excavating coal from deep sources underground.
Shafts are dug down to the coal, or seams that show at the surface are followed
underground. Miners use drills and explosives to break up the coal. Coal is brought to the
surface in small trains, in shuttle cars, or by conveyor belts.
Look at figure 8.4 on page 138 of your text. Why were coal discoveries important to
Canada.
Ans. European settlement of Alberta and the popularity of the steam engines occurred at
about the same time. With no large rivers and Lake Superior to pass, the story of the
settlement of Canada would have been quite different without steam engines.
Coal was used in steam engines (for trains), as well as to power industry and heat
buildings. Today, coal is used primarily for electric power generation.
Look at figure 8.5 on page 139. Why is there a need for land reclamation and how is it
done?
Ans. 1. Remove and store the topsoil before strip mining begins.
2. When the coal has been depleted, use tractors and scrapers to level ridges and grade the
mining area.
3. Bring back the topsoil and spread it out using graders.
4. Use fertilizer and quick-growing plants to prepare the land for farming, pasture, or
wildlife habitat.
When these steps were omitted in the past, an empty scar was left.
Refer to page 140, figure 8.7.
Geologists use a seismic survey to find out what underground rock formations look like.
This helps them identify structures that might contain oil or natural gas. During this type
of survey, shock waves from compressed air guns, thumper trucks, or explosives are sent
through the layers of Earth’s crust. The returning sound waves reflect off rock, are
detected by sensitive equipment, and used to create images of the underground rock
layers. Geologists interpret these images and other data looking for structures that may
contain oil and natural gas. Once seismic crews and geologists have identified possible
oil-bearing reservoir rock formations, it is time to drill for oil.
The Alberta tar sands contain the largest reserve of oil in the world. This area of Alberta
generates 40% of Alberta’s oil production. Since the oil sands are at the surface, open-pit
extraction techniques are used. The oil sand is excavated by shovel and transported by
truck to refineries. The refineries separate the bitumen from the sands. Using this type of
technology, only seven percent of the oil is the sands in recovered. It is hoped that other
on-site techniques will be developed.
Pg. 141 “Did you Know” –
Oil is found in certain geologic formations at varying depths in Earth’s crust. The oil is
usually trapped in a layer of porous sandstone which lies just beneath a dome-shaped or
folded layer of non-porous rock such as limestone. In other formations, the oil is trapped
at a fault or break in the layers of the crust.
The oil in both of these types of geologic formations is usually under such great
pressure that it flows naturally, and sometimes with great force, to the surface. This is
why people refer to a “gusher.”
In most cases, the pressure diminishes with time; in others, there simply isn’t
enough pressure to get the oil to surface to begin with. When this happens, the oil must
be pumped to the surface. One common method of doing this is the pump jack lift
system.
In a pump jack lift system, oil flows into the well through holes or perforations in
the casing. The oil collects in the bottom of the well. The pump jack system lifts the oil to
the surface.
Natural gas or water is sometimes pumped into the well to replace the oil that is
withdrawn. This is called “repressurizing” the oil well and helps to keep oil wells
producing for much longer periods of time.
In your lesson, you will learn how different substances in oil goes through fractional
distillation. Each substance has a unique boiling point, so a substance can be identified
by its boiling point. Distillation separates components of a liquid by boiling and then
condensing them.
Can anyone tell me the difference between complete combustion and incomplete
combustion?
For example, consider the burning of propane. If there is enough oxygen present, propane
and oxygen combine to form carbon dioxide and water. This can be shown as:
C3H8(g) + 5O2(g)  3CO2(g) + 4H2O(g)
If there is a shortage of oxygen, propane and oxygen combine to form carbon
monoxide and water. This can be shown as:
C3H8(g) + 3O2(g)  3CO(g) + 4H2O(g)
Carbon monoxide is a colourless, odourless, and tasteless gas. When inhaled, it
combines with hemoglobin in the red blood cells and prevents hemoglobin from carrying
oxygen in the blood. If a high level of carbon monoxide is inhaled, a person can die
within minutes.
Page 146, look at cellular respiration and combustion reactions. How are these processes
similar?
• Both reactions use oxygen as a common reactant.
• The balanced equations involve the conservation of carbon, oxygen, and hydrogen
atoms.
• The resulting products are carbon dioxide and water.
• Both types of combustion release thermal energy.
We have become reliant on fossil fuels in our lives. What are some of the downfalls to
our use of fossil fuels?
(Have students look at pictures on pages 147 and149)
-non-renewable. Some anticipate that we could run out of fuels by the year 2010. As the
global population continues to grow, there will be more people competing for less and
less fuels.
-oil spills – damage to the environment, devastating to wildlife.
-pollution and greenhouse gases (combustion of gas and diesel fuel releases unburned
fuel, sulphur dioxide, nitrogen oxides, soot, and carbon dioxide into the atmosphere. This
can result in smog, which is a combination of air pollution (smoke) and fog. Some
scientists believe that burning of fossil fuels has resulted in an increase in greenhouse
gases – global climate change.
Acid rain. – kills life in lakes.
Q. Some experts believe we can use fossil fuels for another 100 years before we run
out…others predict we only have 10 years. Why do you think experts might have
different opinions on this subject?
Also discuss that resources have lasted because, year after year, new fossil fuel fields
have been found. Do students think we have just about identified all the oil and gas
resources? What can we do to stretch the date for running out of fossil fuels further into
the future? (Answer: Students might suggest ideas such as:
• Keep searching; there may be more sources.
• Change our ways to use less fossil fuel.
• Find ways to get resources from locations that are currently too expensive to mine.
• Use more renewable energy, such as water, wind, tide, and solar energy.
• Spend more money on space exploration and plan to find resources there.)
Pg. 150 Review. Complete question #1 together.
Go back over previous tutorials for review.