Ethan Evans
February 26, 2015
Variables that Change the Earth Review
1. Draw and label a diagram of the layers of the Earth describing each layer.
2. Define the word weathering and give an example. Weathering is process of breaking rock into soil, sand, and other
tiny pieces. For example, liquid water collects in cracks in a rock. When the water freezes, it expands. The expanding
ice pushes apart the rock and breaks it.
3. Define the word erosion and give an example. Erosion is process of moving sediment from one place to another.
For example, rain, streams, and rivers cause erosion. As water moves across the land, it carries away soil, sand, and
small rocks.
4. Define the word deposition and give an example. Deposition is process of dropping (or depositing) sediment in
new location. When the water slows down, the materials fall out and are deposited, forming deltas and beaches.
5. Give an example of weathering by ice. Draw illustration. Weathering by ice occurs when liquid water collects in
cracks in a rock. When the water freezes, it expands. The expanding ice pushes apart the rock and breaks it.
Ethan Evans
February 26, 2015
6. Given an example of a landform that a glacier would carve out. Draw illustrations.
U-shaped valley.
7. Give at least two examples of weathering by water. Draw illustrations. Some of the minerals in rocks dissolve in
water (weathering). When this happens underground huge caverns can form. Moving water that carries rough
pieces of sand can also chip away rocks. This is also showing erosion—after the rock is weathered and dissolved,
moving water carries it away.
8. Give at least two examples of weathering by wind. Draw illustrations. Wind that contains sand wears away rock
like sandpaper wears away wood. Wind can also move pieces of rock and soil to new places. Wind can create these
desert formations, arches, and dunes
9. Describe nonrenewable resources and list examples. Nonrenewable resources are resources that can’t be used
again. Examples include: Diamonds and Precious Gems, Metal Ore, Fossil Fuels such as Coal, Oil, and Natural Gas.
Ethan Evans
February 26, 2015
10. Describe renewable resources and list examples. Resources that can be used again. Examples of renewable
resources include: Fresh Water via the water cycle, plants via the life cycle, animals via the life cycle, air via the
process of photosynthesis, soil via decomposition of matter and bacteria. Also wind, ocean tides, sunlight, and
biomass are renewable.
11. Describe how you can use renewable resources to generate energy. Which ones are available to us in North
Texas? We can use sunlight to generate electricity by using solar panels and we already know that the sun is the
energy source for the water and for photosynthesis. Wind can be harnessed to store energy as electricity or used
directly to pump water.
12. What causes earthquakes? Plate tectonics. When rocks get stuck along a fault, the plates keep moving. If the rocks
break or slip, the plates move suddenly, and Earth’s crust starts to shake. Earthquakes also happen when one plate
sinks beneath another one, or when plates crash or grind past each other.
13. Describe how earthquakes might affect the surface of the Earth. The shape of the land can change where
earthquakes occur. Earthquakes can also break down landforms and buildings, roads, bridges…
14. Do earthquakes change the Earth quickly or over a long period of time? Quickly.
15. How do volcanoes form? A volcano forms when magma and hot gases escape through openings in the surface of
the Earth. They form as a mountain forms or from hot spots under the ocean.
16. How do volcanoes affect the surface of the Earth? When lava shoots out of the volcano, it hardens and creates new
rock called igneous rock. This lava destroys landforms/habitats that were there.
17. Do volcanoes change Earth quickly or over a long period of time? Both. Volcanoes can benefit the Earth around
them. They bring valuable minerals from the Earth’s mantle to the surface. They provide geothermal energy. Lava
flows can also build new land, as they have in Hawaii.
18. Describe how sedimentary rocks form. Sedimentary rocks are formed when sediment is deposited out of air, ice,
wind, gravity, and settles in layers on the ocean/lake floor or on the surface of land. More layers of sand/sediments
are deposited over time. These layers press down on layers under them. Minerals cement these layers together
and over 1000’s of years they turn into rock.
19. How is soil formed? Every soil originally formed from parent material: a deposit at the Earth’s surface. The material
could have been bedrock that weathered in place or smaller materials carried by flooding rivers, moving glaciers, or
blowing winds. Over time, sun, water, wind, ice, and living creatures help transform, or change, the parent material
into soil by weathering.
20. Describe an experiment that would test properties of soil, clay and sand with water. You could use a jar test (quart
jar with lid, clean water and soil sample) to test the properties of soil. Different soils settle differently when mixed
with water. Sandy soils are light and typically very free draining, usually holding water very poorly due to very low
organic content. Loam soils are somewhat heavier than sandy soils, but also tend to be fairly free draining, again,
due to typically low organic content. Clay soils are not typically free draining, and water tends to take a long time to
Ethan Evans
February 26, 2015
infiltrate. When wet, such soils tend to allow virtually all water to run-off. Clay soils tend to be heavy and difficult to
work when dry. ***You could also test to see which soil retains water the best.
21. Fossils hold clues to the past. What can fossils tell us about the past? How can tree cookies also tell us about the
past? Small animal fossils are one of the best indicators of prehistoric ecosystems and environments. For example, a
fossilized frog tells scientists that the habitat within which it lived must have been wetter because the frog was
dependent on permanent water to breed. Tree cookies can tell us about temperature, amount of rainfall, soil, wind,
sunlight, amount of snow and insects both in the present and in the past.
22. Give at least two examples of how erosion by water changes landforms. Illustrate examples. Wave action is when
waves hit the rocks and pieces of rock break off. The ocean water erodes sand from the bottom of the sea and
deposits it on the beach. Rivers erode sediments along their path and drop them as they flow into the ocean.
23. What are some ways to be able to notice the drastic changes in Earth’s landforms over a long period of time? Take
a trip to the Grand Canyon and observe the unique combinations of geologic color and erosional forms. Record your
observations in a notebook and by pictures/videos that show how often the changes occur.
24. Describe how fossil fuels (coal, natural gas and oil) are formed. They were formed over millions of years ago by
dead plants and animals that were squished between high pressure and temperature to create these nonrenewable
resources. (see sequence chart in science journal page 77)
25. Describe how deltas are formed. Illustrate. Rivers move slowly at the river’s mouth. The river carries a lot of
sediment and mud. The river deposits (drops) the sediment and mud at its mouth. This sediment and mud spreads
out into a fan- like shape, or delta, across the mouth of the river.
Ethan Evans
February 26, 2015
26. Make a three part chart showing 3 landforms created by weathering, 3 landforms created by erosion, and three
landforms created by deposition
(these are only a few examples)
Weathering
Erosion
Deposition
Arches
Canyons getting deeper
Deltas
Sea caves, sinkholes
Caves
Build up of Sand Dunes
Buttes, hoodoos, holes in rocks
River channels in rock, soil
Sand bars
Holes, scrapes, or cracks in rocks
Erosion of a beach
Barrier islands
27. Describe how often you would record changes to landforms if the changes happen quickly? (volcanoes, earthquakes,
landslide)
We would need to record the changes as they occur. If they happen in seconds, we would need to record
every second. If it takes hours, minutes or days, we would need to record changes at those times.
28. Describe how often you would record changes to landforms if the changes happen slowly? (delta formation, dune
buildup, river meanders, erosion of a beach)
We would still need to record changes as they happen, but not as often. If it takes years for a change to
occur, we should record those changes every year.
If it takes hundreds of years then maybe record changes every 10-20 years over a longer period of time. (for
at least 100 years)
29. Describe how a canyon is formed. Illustrate a picture
A canyon forms as a river flows over an area. Over time, the river cuts a channel into the soil and begins to
form a valley. Over 100’s and 1000’s of years the fast flowing river continues to cut through the valley—
eroding the rocks and soil from the riverbed. After 100’s of 1000’s of years, we see steep walls of the
canyon with the narrow river flowing at the bottom, continuing to cut through the rock underneath as the
water flows.
30. What continues to happen to a canyon as years pass?
a. The canyon continues to get deeper, exposing more and more layers of rock, as the river continues to cut
through and erode the riverbed.