Introduction to Earth Science

INTRODUCTION TO EARTH SCIENCE

• Earth Science is the study of the Earth and its neighbors in space.
• Study of the Earth's structure, properties, processes, and 4.5 billion years of biotic evolution.
• Focuses on the four components of the Earth system: land, water, air, and life, and their interactions.
• Scientists in China began keeping records of earthquakes around 780 BCE.
• Ancient Greeks compiled a catalog of rocks and minerals around 200 BCE.
• Mayans tracked the movement of the sun, moon, and planets.
• The first seismoscope was invented in 132 AD by Zhang Heng.
• In the 16th and 17th centuries, inventions like the microscope and telescope made seeing previously hidden worlds possible.
• Eventually, the body of knowledge about Earth became known as Earth science.

Main Branches of Earth Science

• Geology is the scientific study of the origin, history, processes, and structure of the Earth:
  • Includes physical geology studying Earth's structure, composition, and properties.
  • Historical geology is also known as paleontology, uses geology to reconstruct Earth's history.
• Oceanography studies the Earth's oceans, coastal processes, seafloor topography, and marine life.
  • Also known as geological oceanography.
  • It focuses on topography, structure, and geological processes of the ocean floor.
  • Studies how the Earth and oceans formed and how ongoing processes may change them.
• Meteorology studies the atmosphere and the processes that produce weather and climate.
• Astronomy is the study of the universe beyond Earth:
  • Also known as geological astronomy, astrogeology, exogeology, and planetary geology.

Scientific Method

• This is an organized and logical approached to research.
• Involves observation of a phenomenon, event, or "problem," using the senses.
  • Lava from different volcanoes flows at varying speeds related to the lava's viscosity.
• Observations often lead to questions, such as "Does the viscosity of lava impact how quickly it flows?"
• A hypothesis offers a possible explanation or solution to a problem based on known facts.
  • For example, lava with lower viscosity flows faster because of less resistance.
• Experiments are carried out following guidelines.
  • Different liquids with varying viscosities can be tested to simulate lava flow.
  • Factors that can be changed are variables; independent variables are changed by the experimenter.
  • Independent variables are changed by the person performing the experiment; dependent variables change as a result.
  • In most experiments, only one independent variable is tested.
  • In a lava experiment, the independent variable would be the viscosity of the liquid being tested.
  • The dependent variable would be the flow rate of a liquid from the varying viscosity.
  • A control group is a standard of comparison identical in all factors except one.
  • An experiment with a control is a controlled experiment.
• Conclusions are drawn based on the evidence or results.
  • If the results differ from expectations, the hypothesis is changed or discarded.
  • Expected and unexpected results can lead to new questions and further study as well as new knowledge.
  • If low-viscosity liquids flow faster than high-viscosity liquids, the hypothesis is supported and vice versa.
  • If results differ, analyze the possible causes such as inconsistencies in volume, ramp angle, or measurement techniques.

Models of Earth

• Drawings of the Earth's surface have been created to better understand it.
• The first known depiction of the Earth's surface was from the Babylonians in 2,300 В.С.
• Latitude is the angular distance north or south of the equator.
  • Runs east to west and indicates north or south positions.
  • Measured in degrees from 0° at the Equator to 90° at the poles.
  • The Equator is located at 0 degrees latitude.
  • One degree of latitude equals 1/360 of the Earth's circumference.
  • One degree of latitude equals 111 kilometers.
• Longitude is the angular distance east or west of the equator:
  • Runs north to south.
  • Indicates how far east or west a place is.
  • Measured in degrees from 0° at the Equator to 90° at the poles.
  • The Prime Meridian is an arbitrarily chosen meridian which represents 0°.
  • Locations east of the Prime Meridian have longitudes between 0° and 180°E.
  • Locations west of the Prime Meridian have longitudes between 0° and 180°W.
• Minutes - 60 equal parts of each degree
• One minute of latitude equals 1.85 km.
• The distance measured by a degree of longitude decreases toward the poles.
• Geomagnetic Poles are areas where the imaginary poles of Earth’s magnets exist on the surface.
  • The north end of a compass needle points in the direction of the geomagnetic north pole
• Geographical pole is where the axis of rotation intersects its surface.
• Magnetic Declination is the angle between the direction of the geographic pole and the direction a compass points.
• Magnetic North is now drifting faster than 30 miles per year.
• It has already moved back past geological north for the first time in thousands of years.
• A Global Positioning System is a satellite navigation system composed of a global network that transmits radio signals to Earth.
• NAVSTAR was the first GPS satellite which launched in February 1978.
• A globe is a familiar model of Earth that is useful for studying large surface features.
• Cartography is the science of making maps.
• Cartographers walk or drive through an area to make measurements for mapping.
• Remote sensing is the science of obtaining information about objects or areas typically from aircraft or satellites.
• Maps are often made by combining remotely gathered images with field surveys.
• A compass rose is a symbol indicating cardinal directions.
• The legend is a list of symbols and their meanings.
• Graphical Scale - a line with markings like a ruler representing units of measure on the map.
• Fractional Scale - a ratio indicating that 1 unit of distance on the map represents distance on the Earth.
• Verbal Scale - verbalizes the proportion of the map as it relates to real distance ("One centimeter is equal to one kilometer.").
• An Isogram is a line on a map representing constant or equal value.
  • Used to plot data such as measurements of precipitation, temperature, gravity, magnetism, density, elevation, and chemical composition.
• Topographic Maps show the surface features, or topography, of Earth.
  • Shows natural features (rivers, hills) and constructed features (buildings, roads).
  • The elevation above sea level of the land.
  • Elevation is measured from mean sea level.
  • Contour lines show elevation by connecting points with the same elevation.
• Geologic Maps show the distribution of geologic features.
  • Shows types of rocks found in a given area, locations of faults, folds, and other structures.
• Soil Maps classify, map, and describe soils.
  • Based on soil surveys to record soil properties.
  • Valuable for agriculture and land management.
• Diagramming the subsurface is often specialized to Earth science to envision thicknesses and orientations of materials:
  • Diagrams are how earth scientists explain their understanding.