# 2022 Science Midterm study guide

Lesson 1: Scientific Method

• Important terms: hypothesis, independent variable, dependent variable, control, constants

• Hypothesis

• A possible explanation for a set of observations or answer to a scientific question; must be testable

• Independent variable

• The factor that differs between your experimental and control groups. It is what YOU manipulate

• Dependent variable

• The factor that you measure. These measurements DEPEND on the independent variable. Any data that you take is your dependent variable.

• Control

• The group that is tested on so that you can look back and compare it to.

• Constants

• Any aspects of our experiment that are identical in both your experiment and control groups

• Steps of Scientific Method

• 6 steps

• Purpose

• Define the problem. The problem is always in the form of a question. Asking questions is the first step in finding answers!

• Research

• A scientist will begin by researching through many means to aid in his quest in answering his questions

• Hypothesis

• Scientists will think of a possible answer to their problem. Such an answer is called a hypothesis, or an educated guess. It is always in the form of a statement that makes a prediction. It is never a question!

• Experiment

• Carry out a controlled experiment. In this type of experiment, two procedures are always identical in every way except for one

• Analysis

• Record your evidence! Everything about the experiment should be recorded. All of this information is called data

• Conclusion

• Identifying parts of an experiment based on a given scenario

• What should you do if your hypothesis is supported? Not supported?

• Whether or not your hypothesis was supported, good research always raises new problems to be experimented on. So, the scientific method is often considered a continuous cycle!

• Interpreting information presented in a graph and forming a conclusion

• Find avgs based on data given

• What makes an experiment valid

• The experiment must be repeated several times

• The sample size must be large

• The sample group must be chosen at random

• The data collected should be a measurable concept

• Make sure there is only one independent variable

• The experiment must have a control for comparison

• Graphing ( where does the independent and dependent variable belong)

• The independent variable s always placed on the x-axis

• The dependent variable is always placed on the y-axis

Chapter 1: Plate Tectonics

• Important terms: Pangea, fossil, plate, fault, sonar

• Pangea

• A supercontinent that was formed 300 Million years ago

• Fossil

• Any trace of an ancient organism that has been preserved in rock

• Plate

• A section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental and oceanic crust

• Fault

• Breaks in Earth’s crust where rocks have slipped past each other- form along these boundaries

• Sonar

• A system that uses reflected sound waves to locate and determine the distance to objects underwater

• When mid-ocean ridges continually add new material to the ocean floor which results in more crust being added to the ocean floor while at the same time older stipes of rock move outward from either side of the ridge.

• Subduction

• The process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle again

• These processes work together to move the ocean floor as if it were on a giant conveyor belt. The size of Earth’s oceans is determined by how fast crust is being created at mid-ocean ridges and how fast old rust is being swallowed up at deep-ocean trenches.

• Concept of continental drift

• Whose idea, evidence, etc.

• Wegner’s idea is that continents slowly move over Earth’s surface.

• The density of the oceanic crust depends on the location

• Forces that act on rock and what happens as a result

• Different plate boundaries and how they move

• Divergent boundary

• Plates move apart or diverge, from each other

• Convergent boundary

• Plates come together or converge

• Transform boundary

• Plates slip past each other

• Examples of each plate boundary

• Divergent boundary

• Rift valley

• Convergent boundary

• Andes Mountains

• Transform boundary

• San Andreas

• Magnetic striping on mid-ocean ridges

• identical stips on the sea floor

• Distance from the equator and climate

Chapter 2: Earthquakes

• Important terms: stress, tension, compression, shearing, earthquake, epicenter, focus, seismograph, P waves, S waves, surface waves

• Stress

• A force that acts on a rock to change its shape or volume

• Tension

• The stress force that pulls on the crust and thin rock in the middle

• Compression

• The stress force that squeezes rock until it fields or breaks

• Shearing

• Stress that pushes a mass of rock in two opposite directions

• Earthquakes

• The shaking and trembling that result from the movement of rock beneath the Earth’s surface

• Epicenter

• The point on the surface directly above the focus

• Focus

• The area beneath Earth’s surface where rock that was under stress begins to break or move.

• Serimograph

• An instrument that records and measures an earthquake’s seismic waves

• P waves

• Seismic waves compress and expand the ground like an accordion. First waves to arrive; primary. Can travel through solids and liquids

• S waves

• Seismic waves can vibrate from side to side or up and down. Their vibrations are at a right angle to the direction they travel. When they reach the surface they shake structures violently. Cannot pass through liquids. Secondary

• Surface waves

• Waves move slower than primary and secondary waves. They produce severe ground movements. They produce movement that is similar to waves in water, where the water’s particles move in a pattern that is almost circular. They can make the ground roll like ocean waves or shake buildings from side to side

• Causes of an earthquake

• Forces of plate movement ( a release of stress) cause the rock to break, resulting in the shaking of the Earth’s surface

• Types of stress and how they move Earth’s crust

• Tension

• Pulling in opposite directions

• Thins the rock in the crust

• Compression

• Pushing together

• Forces that squeeze rock until it folds or breaks

• Shearing

• Pushing in opposite directions

• Causes rock to slip apart or change shape

• Where do earthquakes occur

• Faults

• How do seismic waves move? Need to know all 3

• P waves

• Compress and expand the ground like an accordion (travel through solids and liquids)

• S waves

• Vibrate side to side or up and down; only travel through solids and shake structures violently

• Surface waves

• Move almost like a water wave (circular); these waves form when S and P waves reach the surface

• Three Different scales to measure the magnitude of an earthquake

• Modified Mercalli Scale

• Based solely on human observation

• Richter Scale

• Rate earthquakes based on the size of waves

• Moment Magnitude Scale

• Rate earthquakes based on the amount of energy released

• Different types of faults and examples of each

• Normal fault

• Rio Grande River

• Reverse fault

• Northern Rocky Mountains

• Strike - Slip Fault

• San Andreas

• Anticline vs. Syncline

• Anticline - a fold in the rock that bends upward into an arch

• Syncline - a fold in the rock that bends downward to form a V shape

Chapter 3: Weathering and Soil

• Important terms: Erosion, Weathering, abrasion, permeable, soil, bedrock, humus, loam, oxidation

• Erosion

• The process of wearing down and carrying away rocks.

• Weathering

• The process that breaks down rock and other substances.

• Abrasion

• Refers to the wearing away of rock by rock particles carried by water, ice, wind, or gravity

• Permeable

• This means a material is full of tiny connected air spaces that allow water to seep through it

• Soil

• The loose weathering material on Earth’s surface in which plants can grow

• Bedrock

• The solid layer of rock beneath the soil

• Humus

• A dark-colored substance that forms as plant and animal remains decay

• Loam

• Soil that is made up of about equal parts of clay, sand, and silt. The best soil for growing most plants

• Oxidation

• Iron combined with oxygen in the presence of water

• Factors that affect the rate of weathering

• Heat, cold, water, ice, and gases

• Chemical vs Mechanical weathering

• Mechanical - when a rock is physically broken down into smaller pieces

• Chemical - when rocks and minerals undergo changes in their chemical makeup

• Agents of weathering ( Mechanical and Chemical)

• Mechanical

• Animal actions

• Freezing and thawing

• Plant growth

• Release of pressure

• Abrasion

• Chemical

• Water

• Oxygen

• Carbon dioxide

• Living organisms

• Acid rain

• Properties/characteristics/makeup of the soil

• Compositions, Fertility, texture, pH

• Layers of soil

• C Horizon - forms as bedrock begins to weather. The rock breaks up into small particles

• A Horizon - topsoil; forms as plants add organic materials

• B Horizon - forms as rainwater washes these materials down from the A horizon

• Weathers away marble and limestone

• carbon dioxde

Chapter 4: Erosion and Deposition

• Important terms: erosion, deposition, sediment, runoff

• Erosion

• The process by which natural forces move weathered rock and soil from one place to another

• Deposition

• What occurs where the agents of erosion deposit, or lay down, sediment. It changes the shape of the land

• Sediment

• The material erosion moves; may consist of pieces of rock or soil or remains of plants and animals.

• Runoff

• The moving water carries particles with it.

• Difference between erosion and deposition

• Erosion moves materials around while depositions lay down the sediments from erosion

• Types of erosion

• Water, Glacial, wind, and wave

• Landforms due to water erosion and deposition

• Water erosion

• Waterfalls

• Flood plains

• Meanders

• Oxbow Lakes

• Water deposition

• Alluvial fans

• Deltas

• Glacial erosion and deposition - what landforms were created by each?

• Glacial erosion

• Horn

• Cirque

• U-shaped valley

• Arete

• Glacial deposition

• Fiord

• Glacial lake

• Morain

• Drumlin

• Kettle

• Contributions to runoff

• Vegetation

• Amount of rain

• Type of soil

• Shape of land

• Land’s use

• Landforms created by water and wave erosion

• Water erosion

• Flood plains

• Meanders

• Oxbow LAKES

• Wave erosion

• Wave-cut cliff

• Sea cave

• Sea arch

• Sea stacks

• Karst topography

• A region in which a layer of limestone close to the surface creates deep valleys, caverns, and sinkholes

• How do rills become rivers?

1. Many rills come together to form a gully

2. Gullies join together to form a larger channel: stream

3. As streams merge together, they form a larger body of water called a river

• Movement of different-sized sediment

• Fine particles

• carries through the air

• Medium particles

• skip or bounce

• Large particles

• slide or roll

Chapter 5: Geologic Time

• Important terms: geologic time scale, era, period

• Geologic time scale

• A record of the geologic events and the evolution of life forms as shown in the fossil record

• Era

• Three long units of time geologists use to divide the time between Precambrian Time and the present

• Period

• The subdivisions of geologic time for eras

• Precambrian time

• The long span of time that began geologic time. It covers 88% of Earth’s history and ended 542 myo. Few fossils survived from this time period

• Order of the eras and periods

• Cenozoic Era, Mesozoic Era, Paleozoic Era, Precambrian Time

• Quanternary Period, Neogene Period, Paleogene Period, Cretaceous Period, Jurassic Period, Triassic Period, Permian Period, Carboniferous Period, Devonian Period, Silurian Period, Ordovican Period, Cambrianj

• Organisms created in each period

• Precambrian Time

• Single-celled organisms

• Cambrian

• Trilobites

• An explosion of new life

• Ordovician

• Vertebrates evolve; including jawless fish

• Silurian

• First land plants evolve

• Fishes become common

• Devonian

• Age of the fishes

• Animals reach land

• Amphibians

• Carboniferous

• Reptiles

• Giant insects

• Ferns

• Permian

• Reptiles evolve

• Mass extinction

• Triassic

• Reptiles flourish

• Dinosaurs appear

• Jurassic

• Dinosaurs become common

• First birds evolve

• Cretaceous

• Birds replace flying reptiles

• First flowering plants appear

• Paleogene

• Mammals flourish

• Neogene

• Mammals and birds become large

• Quaternary

• Humans evolve

• Organisms

• Test setup: 32 matching, 35 multiple choice, 7 T/F, 1 scenario based question, Labeling diagram, 1 SA, 1 essay

• Total Points: 120 points