Download Grade 8 Unit 4 What is a Cycle Test Revew

Unit 4 – What is a cycle? Test Review KEY
Moon Phases and Occurrences:
1. Explain why the Earth experiences day and night:
Earth’s rotation on its axis.
2. How long does it take Earth to rotate once on its axis?
24 hours
3. How long does it take the Earth to make a complete revolution around the Sun?
One year, 365 ¼ days
4. Why does the Earth have seasons?
The Earth’s axis is tilted as it revolves around the sun; changing the amount of
direct sunlight an area receives
5. Label this diagram that shows the positions of the Earth in relation to the sun
during the four seasons.
6. When the north end of the Earth’s axis is tilted toward the sun, explain why
North America will experience longer days.
The Northern Hemisphere is pointed towards the sun, which means we are
experiencing summer. During summer, the daylight lasts longer because the
northern hemisphere is receiving more direct sunlight, which means the sun has
a longer path in the sky.
7. Why don’t we see the far side of the moon?
The moon rotates and revolves at the same rate – 27.3 days
8. The phase of the moon you see depends on what?
How much of the sunlit side of the moon faces the Earth.
9. From a new moon phase to a full moon phase, how does the illuminated side of
the moon change?
We see an increasing amount of the lighted side of the moon.
10.Shade in and label the moon phases in the diagram below.
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11.
A student builds a model based on the diagram. The student uses foam balls
to represent the moon and Earth and a flashlight to represent the sun. The
student should shine the flashlight on the model of Earth from Position __4_ to
represent the middle of the cycle?
12. What is the difference between a solstice and an equinox?
Solstice – our longest and shortest day of the year. (June and December) The
noon sun is directly overhead the southern or northern hemisphere.
Equinox – two days in the year when the hours of daylight equal the hours of
darkness. (March and September) The noon sun is directly over the equator.
13.What causes tides?
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The gravitational pull of the moon on the Earth’s waters. (and a little bit of the Sun’s
gravity too)
14.What is a Spring tide? Then, draw the positions of the Earth, Moon, and Sun.
The tide with the greatest difference between the low and high tide. Spring tides occur
at full and new moon. The Sun, Moon and Earth are lined up like this:
15.What is a Neap tide? Draw the positions of the Earth,
Moon, and Sun.
The tide with the least difference between the low and
high tide. Neap tides occur at first and last quarter
moons.
16.How would the ocean tides be affected if Earth did not rotate on its axis?
There would not be two high tides and two low tides each day
!
17.
Using the tidal chart above, what is the height and time for the first high
tide on Days 1 and 2?
Day 1: ___1.8 meters at 2 am______________________________________
Day 2: ___2 meters at 3 am____________________________________
Oceans and Weather:
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1.What causes temperatures at the equator to be warmer than near the poles?
The equator receives more direct sunlight due to the tilt of the Earth
2.How does the ocean affect the climate of coastal areas during the summer? What about
during the winter? Summers will be cooler and winters will be warmer than they would be
otherwise
3.Using
the current map below, describe the climate of the west coast of North America ,
from Alaska to Mexico. Explain how ocean currents contribute to the weather. The climate
will be cooler in the coastal regions because of the cold current that runs the length of
the west coast of North America. Ocean currents act much like a conveyer belt,
transporting warm water and precipitation from the equator toward the poles and cold
water from the poles back to the tropics. Thus, currents regulate global climate, helping
to counteract the uneven distribution of solar radiation reaching Earth’s surface. Without
currents, regional temperatures would be more extreme—super hot at the equator and
frigid toward the poles—and much less of Earth’s land would be habitable.
4.
Why do Land Breezes occur?
The land cools down quickly
while the sea stays warm. Above
the sea, warm air rises and the
wind blows away from the coast
toward the sea.
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5.
Why do Sea Breezes occur?
The land heats up more quickly than
the sea. Above the land, warm air rises
and the wind blows toward the coast
from the sea.
6. What is the primary energy source for weather events on Earth? The Sun!
7. Below is a list of cities and their temperature ranges. Explain why these cities have
different temperature ranges. San Diego and Charleston are located along the coast,
so their climates are moderated by the ocean. Salt Lake City and Boulder are located
inland far from the coast, so the land cools off and heats up quickly making a wider
range of temperatures.
-San Diego has a temperature range of 10
-Charleston, SC has a temperature range of
11
- Salt Lake City, UT has a temperature range
of 21 - Boulder, CO has a temperature range of 31
8.
What causes wind to form? Differences in air pressure – the bigger the
difference the stronger the wind
9. Fill in the circles below with a picture demonstrating molecules of warm water vs
molecules of cold water. Which one is denser? Explanation: molecules with less (heat)
energy are closer together, make the water denser, i.e. more molecules packed into a
smaller amount of space
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Warm Water (less dense)
!
Cold Water (more dense)
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10. Color the convection current below. Explain in the blank space next to the picture why
the warm air is at the top and why the cold air is lower in the house. Explanation:
Warm air/water rises and cold air/water sinks, creating circulation patterns. Density
changes as substances that are fluid are heated and cooled. Density decreases as the
molecules heat up and therefore air rises. As it cools, the density increases and the air
sinks.
11.What are the weather conditions associated with a low pressure system? Why? (explain
how a low pressure system works)
Cloudy and rainy; because the air particles near the center of a low pressure system
have a lower density so they tend to rise. (Low pressure is associated with rising air)
Basically, air cools as it rises, which can cause water vapor in the air to condense into
liquid water droplets, sometimes forming clouds and precipitation
12.What are the weather conditions associated with a high pressure system? Why? (explain
how a high pressure system works)
Clear and sunny; because the air particles near the center of a high pressure system
have a higher density so they tend to sink. (High pressure is associated with sinking
air) Air is moving away from the high pressure center at the surface (or “diverging”)
so as a result, air from above must sink to take its place
These images may help you remember:
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13.What affect do oceans have on the overall global climate?
The ocean keeps the planet’s overall temperature moderate, not too hot and
not too cold (The goldilocks affect ☺ )
14.
Fill in the chart:
Type of
Front
Description
Cold
Cold fronts occur
Thunderstorms often occur Clear, crisp air
when a colder, drier
follows a cold
air mass pushes out
front
a warmer, wetter
one
Warm
15.
16.
17.
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Warm fronts occur
when a warmer air
mass pushes out
cooler, drier air
Weather it brings
Weather after the Symbol
front
Fog often occurs, light
rain–
Usually warm
humid days follow
a warm front
!
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What direction do fronts typically move in the U.S.? West to East
Why do winds seem to curve to the right in the Northern Hemisphere and
curve to the left in the Southern Hemisphere? The Coriolis Effect – the Earth is
rotating counterclockwise
Wind always moves from High pressure to Low pressure.
= sunny, !
= cloudy, !
= wind blowing from NE to SW
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18. . What does the symbol shown at the right tell you about the weather conditions?
Cloudy and the wind is blowing from the northwest toward the southeast at 20 knots
19. Fill in this chart on isobars:
Type of Pressure
Wind Speed
Distance between isobars
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High
Lower wind speeds
Far apart
Low
Higher wind speeds
Closer together
20. How does the ocean temperature increase cause weather changes during an El Nino year?
El Niño is defined by prolonged warming in the Pacific Ocean sea surface temperatures (1-2
degrees). Global wind patterns shift, this causes warmer temperatures, meaning more
evaporation and precipitation East of its usual place. This anomaly happens every 2-7 years.
During the El Nino weather patterns change around the world, in particular, the southern US
(including Texas) gets more rain than normal. *Review in textbook!
21.Describe a la Nina weather pattern. The jet stream moves north which causes snowfall to
increase in the Pacific Northwest and even over by the Great Lakes. Southern US gets less
rainfall. More hurricanes form in the Atlantic Ocean. More rain in SE Asia, drought in
South America.
22.Why do hurricanes usually form off the coast of Africa? The water temperature is warmer
at the equator. A hurricane needs the warm water of the tropics, which feeds a storm
with energy, in order to form. The atmosphere must be laden with moisture in the air to
create a storm.
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23.Why does a hurricane lose strength when it moves from the ocean onto land? They
lose their source of heat and moisture. Friction over land also reduces the circulation
of surface winds, weakening a hurricane
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