Transcript SNC2P (3.3) Ans _ HW

3.3 Answers
LC p.215
2. Explain why the Sun is the most important
influence on Earth’s climate.
•
The Sun is the most important influence on
Earth’s climate because the Sun’s solar
energy is responsible for the temperature on
our planet.
LC p.215
3. Use figure 3.9 to explain why it is warmer in the
northern hemisphere in summer than during the
other 3 seasons.
• In the northern hemisphere in summer, Earth is tilted
toward the Sun. The angle allows for solar energy to
strike the region more directly, causing warmer
temperatures than in the other three seasons.
LC p.217
1. Explain why the atmosphere is a heat
sink.
•
The atmosphere is a heat sink because it
traps and stores heat and allows it to even
out the distribution of heat over the day.
LC p.217
2. Use figure 3.11 to explain how the warming and
cooling of air generates wind.
• Wind blows, heating the air. Warm air will expand
and rise. As it rises, it causes wind to form. The wind
rises but cools as it reaches higher latitudes. The air
cools down and then sinks. Cool air is attracted to
heat, so it moves as wind to warm areas, staring the
heat transfer cycle again.
LC p.217
3. Explain why Earth receives more direct
energy at lower latitudes than at higher
latitudes.
• Earth receives more direct solar energy at
low latitudes than at higher latitudes
because of the way the Earth is tilted
3.3 More Answers
LC p.219
2. Predict what would happen if the
concentration of greenhouse gases in the
atmosphere increased.
• Predictions may vary. For example: If the
concentration of greenhouse gases in the
atmosphere increased, the Earth would become
very hot. Vast deserts would form, and plant and
animal life would not be able to survive
LC p.219
3. Why might scientists believe that water
vapour accounts for so much of the
greenhouse effect?
• Approximately 70% of the Earth’s surface
is covered with water, so scientists believe
that water vapour accounts for 70% of the
greenhouse effect.
LC p.221
1. Water can absorb a lot of heat before its
temperature rises. Explain how this
moderates air temperature.
•
Water moderates air temperature by absorbing
a lot of heat from Earth’s atmosphere before
getting warm and releasing the heat again. It
helps to cool Earth and warm it again when
necessary.
LC p.221
2. What is a carbon sink, and how does it
moderate air temperature?
• A carbon sink is something that absorbs and
stores carbon dioxide from the atmosphere.
Oceans act as a carbon sink. By storing carbon
dioxide, the oceans keep the gas from warming
Earth too much. When there is less carbon
dioxide in the air, the oceans will release the gas
to allow for Earth to warm up. This will keep Earth
from getting too cool.
LC p.225
1. In your own words explain why Earth’s climate
is a challenge to understand and make
predictions about.
•
Earth’s climate is a challenge to understand and
make predictions about because everything has
an effect on other things. The heating of Earth has
an effect on wind and ocean currents, which affect
climate change. Natural features like mountains
and volcanoes also affect wind patterns, which in
turn affect precipitation patterns and so on. Every
system and event seems to be connected to
climate change.
LC p.225
2. Explain why it is hard to understand how an
increase in atmospheric water vapour will affect
climate.
• It is hard to understand how an increase in
atmospheric water vapour will affect climate
because when surface temperatures increase,
more water evaporates from soil and water. More
water vapour goes into the atmosphere to warm the
Earth. But more water vapour also means more
clouds form. Clouds reflect solar energy, therefore
cooling the Earth. More clouds also mean more
precipitation in some parts of the world. So it is
hard to predict how the climate will change.
LC p.225
3. How can increased atmospheric carbon dioxide lead to
both higher and lover temperatures in different regions,
and yet still cause global warming?
• Carbon dioxide heats the Earth, which causes the oceans to
heat up. As water warms, ocean currents that would have
been generated by sinking cold water start to slow down.
This changes both warm and cold currents. When these
currents change, temperatures in surrounding regions
change, which in turn affects precipitation patterns. Carbon
dioxide causes global warming because it is a greenhouse
gas that absorbs and then radiates heat, therefore warming
the planet
Activity 3.6
What Did You Find Out?
1. The cold water moved to the bottom of the warm water
beaker. The warm water moved to the top of the beaker.
You could see a current being created. This shows how
oceans transfer heat. The cold water is denser than warm
water, so it sinks to the lower depths. It displaces the warm
water around it. This produces a current.
2. Change the cold water beaker to coloured, salty water at
room temperature. Add two tablespoons of salt to 250 mL of
room temperature water. Change the beaker with warm
water to one with room temperature water. Transfer some of
the salty water to the unsalted water beaker. You should
see the same current effect as with the cold and warm
water.
Activity 3.7
What Did You Find Out?
1. The colour of the light changed from being
bright white to a pale yellow then greyish as
more creamer was added to the water. The
creamer (ash) seemed to block the light passing
through the water.
2. This activity models the effect of volcanic ash in
the atmosphere by showing how little light can
get through the water (atmosphere) once the
creamer (ash is added).