Class Notes 2024

Measurement and Motion

I. Density

A. measures how much mass is in a volume of a substance (measure of compactness)

B. Formula is:  Density = Mass

                                        Volume

C. The unit used is often g/cm3 or g/ml

D. If an object is cut in half, density does not change.

E. The density of water is 1.0 g/cm3. 

            -things float that are less dense than water

            -things sink that are more dense than water

Inside Earth

I. Earth’s Interior

A. Geologists (study Earth’s materials) use rock samples and seismic waves (produced by earthquakes) to learn about Earth’s interior.

B. Layers include the crust (dry land and ocean floor), mantle (very hot rock material), outer core (liquid metal that produces magnetic field), and inner core (dense solid metal)

C. Diagram: 

II. Earth’s Mantle
A. Heat from Earth’s core causes convection currents within the mantle.
B. Enough heat is transferred to allow solid mantle rock to flow very slowly from the bottom to the top.
C. When rock material cools down, it sinks back to the bottom of the mantle.
D. Convection Current Diagram:

III. Continental Drift

A. Alfred Wegener (meteorologist) proposed that continents have moved based on land features, fossils, and evidence of climate change.

B. Wegner claimed that continents drifted together to form a supercontinent that he called Pangaea, which means “all lands.”

C. Many rejected his idea because Wegener was unable to explain how continents moved.

IV. Theory of Plate Tectonics
A. The lithosphere (Earth’s crust and upper part of the mantle) is broken into sections called plates which move slowly over time due to convection in the mantle.
B. Plate edges meet at boundaries called “faults.”
C. Plates can move apart (divergent boundaries), come together (convergent boundaries), or slide against one another (transform boundaries)

D. Different boundaries can form different geographic features

             *Divergent boundaries= mid-ocean ridges (in water) or rift valleys (on land)

             *Convergent boundaries=mountain ranges and deep ocean trenches

             *Transform boundaries can often cause earthquakes

V. Earthquakes

A. The focus is the area that triggers the earthquake, and the epicenter is the point on Earth’s surface above the focus.

B. Produce seismic waves, which carry energy as they travel.

    *P waves=primary (first to arrive)-crust vibrates forward and back

    *S waves=secondary (arrive after P waves)-crust vibrates side to side

    *Surface waves=move the slowest but produce severe ground movements

C. Tsunamis (large waves) may occur if earthquakes happen in ocean crust.

VI. Rocks
A. There are 3 basic types that form in different ways.
        1) Sedimentary (ex: coal, shale) =forms when pieces of materials are pressed together (may have fossils or clear layers within them)
        2) Metamorphic (ex: marble) = form when rocks are put under heat and pressure.  If they are “foliated” it means that grains (particles) are arranged in parallel lines.
        3) Igneous (ex: granite) = forms from cooling of magma/lava.
B. The rock cycle changes rocks into new forms over time.

Earth's Changing Climate

I. Earth’s Climate Basics

A. Climate is defined as weather patterns over a long period of time.

B. Climate data shown over a long period of time are able to show trends (shorter amounts of time show fluctuations).

C. Over time (since the late 1800’s), there has been a trend observed where temperatures on Earth have increased, while the amount of ice has decreased.

II. Earth’s Atmosphere

A. It is defined as the mixture of gases surrounding the planet.

B. The two most abundant (common) gases in Earth’s atmosphere are Nitrogen (78%) and Oxygen (21%).

C. Oxygen begins to increase greatly when organisms (living things) capable of photosynthesis evolve on Earth (over 2 billion years ago).

D. Other gases within the atmosphere include Methane (CH4), Water Vapor (H2O), Carbon dioxide (CO2), and Sulfur Dioxide (SO2)

III. The Greenhouse Effect

A. Defined as the process that occurs when gases in Earth's atmosphere trap the Sun's heat. 

B. These heat trapping gases include carbon dioxide (CO2), methane (CH4), and water vapor (H2O).

C. Without greenhouse gases our planet would be too cold, and life as we know it would not exist (heat from the sun would escape into space).

D. Sunlight,with the natural greenhouse effect process, makes the earth habitable. 

IV. Human Activity and Climate

A. Today, scientists agree that Earth is getting warmer due to greenhouse gases that are being released into the atmosphere.

B. Human activities that increase greenhouse gases include: combustion (CO2 released when burning fuel), raising livestock (which releases methane),  and deforestation (cutting down or burning forest areas).

C.  Ways to lessen human impact include: developing other energy sources (using less fossil fuels), changing livestock diets or decreasing meat production, regrowing forest areas, and capturing carbon dioxide and storing it. 

Oceans, Atmosphere, Climate, and Weather Patterns (OACW)

 I. Temperature and Heat Transfer

A. Temperature is a measure of how hot or cold a substance  (hot substances have faster moving particles/atoms than colder substances) 

B. Liquid thermometers can measure temperature (in Celsius or Fahrenheit) because the alcohol inside expands when heated (so it rises), and contracts when cooled (so it shrinks).

C. Heat is the transfer of energy (thermal) from hotter objects to cooler ones.

D. Heat is transferred in 3 ways which includes radiation (through space), conduction (physical contact), and convection (gases and liquids rising and sinking).

II. Energy Transfer and Air Temperature

A. The sun’s radiation heats Earth’s surface, which can then heat the air above it (the air is not heated by the sun directly).

B. Air closer to the ground will be warmer due to conduction (direct contact with the surface).  This warm air will then rise, cool, and sink back down (convection current cycle).  

C. Areas close to the equator (0 degrees latitude and tropical) receive more direct sunlight on the surface, which leads to higher air temperatures.

D. Areas further from the equator tend to have cooler temperatures (less direct sunlight) due to less direct sunlight hitting the surface.

III. Ocean Currents

A. Ocean currents are streams of water that move in regular and predictable patterns (some may form circular gyres). 

B. Ocean currents from the equator can bring warm water to cooler areas, which can warm the air as a result. 

C. Ocean currents from the poles can bring colder water to warm areas and cool the air as a result. 

D. The direction of the wind in an area (prevailing wind) and location of continents affect ocean current direction. 

IV. Water in Air

A. Liquid water warms, evaporates, and then becomes water vapor (gas) in the air.

B. Water vapor cools and turn into a liquid (condensation) which forms clouds that can release precipitation (rain, sleet, snow).

C. More rainfall is common in air masses (air parcels) that lose more energy and cool.

D. An air mass that is warmer than surrounding air will rise, lose energy, and cause rainfall.

V. Air Pressure and Wind

A. Air pressure is the weight (or force) of air molecules pressing down on Earth’s surface (measured with a barometer in inches of mercury or millibars).

B. When air heats, it becomes less dense, so air pressure decreases. Since there is unequal heating on Earth, there are areas where pressure is high and low at different times. 

C. Winds (speed measured with anemometers) are caused by differences in air pressure. Air moves from areas of high pressure to low pressure (think of squeezing a balloon). 

Earth, Moon,  and Sun

I. Earth’s Movement in Space

A. Rotation= the spinning of Earth on its axis (causes day and night)

     -about 24 hours per rotation

B. Revolution=Earth orbits around the sun in 365.25 days (the .25 is why we have a leap year)

II. Seasons

A. Tilt of axis (23.5 degrees) results in Earth’s seasons (NOT DISTANCE FROM SUN)

B. Northern Hemisphere Solstices and Equinoxes:

      1. Summer Solstice= June 20/21 (longest day)

      2. Winter Solstice= Dec. 21/22 (shortest day)

              3. Vernal (Spring) Equinox = March 19/20  (equal day/night)

              4. Autumnal (Fall) Equinox= Sept. 22/23 (equal day/night)

C. Southern Hemisphere has opposite season of Northern Hemisphere

III. Gravity
A. Force that attracts all objects toward each other

B. Measured in Newtons (N)

C. Strength of gravity between 2 objects depends on mass (amount of matter) of objects and the distance between them.

D. The force of gravity on an object is its weight.

E. Law of Universal Gravitation states that every object in the universe attracts every other object.

IV. Moon

A. Likely formed due to an early Earth collision with another planet sized object (Collision Ring Theory)

B. Rotates so that the “near side” always faces Earth and the “far side” always faces away.

C. Phases occur as it revolves around Earth, and the phase depends on how much of sunlit side faces Earth.

D. Waxing = appears to gain light 

     Waning= appears to lose light            

V. Eclipses

A. Occur when the moon’s shadow hits Earth (solar eclipse) or the Earth’s shadow hits the moon (lunar eclipse)

B. Solar eclipses occur during the New Moon phase and Lunar eclipses occur during the Full Moon phase.

C.Total eclipses occur in the umbra and partial eclipses occur in the penumbra.

Scientific Method and Geology on Mars

I. Scientific Method

A. Series of steps taken to investigate a question or problem

B. Usually includes identifying a problem, researching, testing a hypothesis

C. The last step is often to “form a conclusion” based on the data (information collected).

II. Hypothesis

A. an educated prediction

B. proved accurate by collecting data (information) and duplicating (repeating) experiments and tests

C. if supported repeatedly, without being disproved (proven untrue), it can be included as part of a theory

III. Observations, Inferences, and Variables

A. Observations are made using the senses and can be quantitative (numbers or measurements) or qualitative (colors, texture etc.)

B. Inferences are conclusions based on observations.

C. Variables are the factors within an experiment.

      -Independent Variable (IV): the one thing being tested in an experiment or the one difference between the groups or trials. 

      -Dependent Variable (DV): whatever is being measured in an experiment to form the conclusion. 

      -Control Variables (CVs): the parts of an experiment that need to stay the same in in all groups and trials.

D. Experiments are valid (reliable) if they can be duplicated (repeated) by others, and the same result is found.

IV. The Rocky Planets

A. Inner solar system has 4 rocky planets (Mercury, Venus, Earth, Mars) with solid surfaces (gas giant planets are in the outer solar system).

B. Each planet is a system consisting of 4 spheres.

-Geosphere: surface and interior (inside) of the planet      

-Hydrosphere:any water on the planet

-Atmosphere: gases that surround the planet

-Biosphere: living organisms on the planet

C. If a planet is habitable, it means that living organisms can survive there (only Earth is known to be habitable as of now) 

V. Geologic Processes and Landforms

A. Landforms such as mountains, valleys, plateaus, and channels exist on the 4 rocky planets.  

B. These landforms exist because of geologic processes such as water movement, lava flow, and wind erosion (movement of sand/soil due to air movement).

C. If landforms on different planets look similar, then it may be because they were formed in similar ways.

D. Scientists will often use models to show how geologic processes form different landforms.  Models may be physical (like stream tables) or digital (computer models). 

VI. Graphing Data Steps

1. Form Appropriate Title

2. IV (independent variable) on X-axis

3. DV (dependent variable) on Y-axis

4. Determine appropriate ranges (spread data out)

5. Plot data and connect lines (or make bars)