Question of the Day
Question: What causes the greenhouse effect
and why is it important?
Answer: … … …
p. 605 CYU 2-7
p. 605 CYU 2-7
2.
Identify which of the following gases is most
abundant in Earth’s atmosphere today.
a. argon
c. oxygen
b. nitrogen
d. carbon dioxide
2. Nitrogen is most abundant in Earth’s atmosphere
today.
3. Compare Earth’s early atmosphere with its present atmosphere.
3. Earth’s early atmosphere was composed of many gases that would be
poisonous to us today. As life forms evolved and began to photosynthesize,
oxygen was produced. Once animals adapted to breathing oxygen, they began
to give off carbon dioxide, balancing the production of oxygen.
p. 605 CYU 2-7
4.
Arrange the steps of the oxygen-carbon
dioxide cycle in the correct order:
a.
b.
c.
d.
Animals breathe oxygen
Plants produce oxygen
Plants use carbon dioxide
Animals exhale carbon dioxide
4. The correct order is b, a, d, c.
b.
a.
d.
c.
Plants produce oxygen
Animals breathe oxygen
Animals exhale carbon dioxide
Plants use carbon dioxide
p. 605 CYU 2-7
5. Explain why the
following statement is
incorrect: global warming
could cause oceans to rise,
so the greenhouse effect
must be eliminated
completely.
5. If we were to eliminate
the greenhouse effect
completely, the world’s
climate would become too
cold for humans to survive.
p. 605 CYU 2-7
6. Predict how much colder it is at the top of Mount Everest, which is almost
9km above sea level, than it is at the Indian coastline. Consider only the
difference in altitude. (Hint: the temperature in the troposphere decreases by
6°C/km)
6. The temperature at the
top of Mount Everest is
about 54°C colder.
9km x 6°C/km = 54°C
p. 605 CYU 2-7
7. In 1982, Larry Walters rose to an
altitude of approximately 4900m (just
over 3 miles) on a lawn chair attached
to 45 helium-filled weather balloons.
Give two reasons why Walters’s
efforts were dangerous.
7. Walters’s efforts were dangerous
because the oxygen content of the air
is considerably lower at that altitude
and the temperature is extremely
cold.
Relative Humidity
Humidity
 the measure of the amount of water
(moisture) in the air
 high humidity = lots of water in the air
Saturated
 when the air is holding the maximum
amount of moisture that it can hold at a
particular temperature
 warm air can hold more water vapor than
cold air
Absolute Humidity
 actual amount of water in a given volume of
air
 Units are g/mL
Capacity
 The maximum amount of water the air can
hold at a specific temperature
 If the air is holding its full capacity of water
vapor it is saturated.
Relative Humidity
 how much water is in the air relative
(compared) to its capacity at a specific
temperature
 = Absolute Humidity X 100
Capacity at a Particular
Temperature
Psychrometer/Hygrometer
 instrument used to
measure relative humidity
 contains both a wet and a
dry bulb thermometer
Dew Point
 Temperature to which the
air would have to be cooled
to make the relative
humidity 100%
 condensation can begin at
this temperature
Dew Point
 if below freezing, water will go from vapor to
ice crystal
 the higher the
temperature the more
moisture it takes to
reach the dew point
 In general:
– High dew points = high humidity
– Low dew points = low humidity