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Introduction to Earth Science Scientific Measurement A. Observations - using the senses to gather data (information) from the environment - May extend the senses through the use of certain tools - Two types of observations Scientific Measurement 1. Qualitative Observations - describe properties of an item that are not easily measured - (Ex.: color, shape, texture, etc,) Scientific Measurement 2. Quantitative Observation - observations where a property can be measured using a tool that extends the senses - (Ex.: length, mass, volume, etc.) Scientific Measurement B. Measurements 1. Length - distance between two points - Depending upon the item being measured, it may also be width or height Scientific Measurement 2. Volume - how much space an object takes up - For regular solids (cubes, rectangular prisms, cylinders, spheres, etc.) the volume can be calculated using a formula Scientific Measurement - Volume of rectangular solids: - V=lxwxh - Volume of cylinder: - V = x r2 x h - Irregular solid volume is determined using water displacement (Archimedes’ Principle) Scientific Measurement 3. Mass - how much matter an object contains - Determined by using a balance (either triple-beam or digital) QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Scientific Measurement 4. Time - measured using a stopwatch 5. Temperature - measured with a thermometer - For most measurements, temperatures are recorded on the Celsius scale Scientific Measurement - For weather variables, temperatures are recorded on the Fahrenheit scale Scientific Measurement C. Density - describes how much mass is found in an amount of space - density is constant for substances at given temperatures ex.: water's density at 4.0 C is always 1.0 g/cm3 - density can change Scientific Measurement - in general, density decreases as a substance is heated - in general, density increases as a substance is cooled Scientific Measurement - density is also affected by pressure - if the same amount of mass is compressed (squished) into a smaller space, the density increases - if the pressure on an object, like a gas, decreases, its volume will expand while its mass stays the same, causing the density to decrease Scientific Measurement - exception = water density decreases as it is cooled (ice floats in liquid water) - density can be calculated using the following equation: Scientific Measurement D=M/V D = density M = mass V = volume / = divided by Scientific Measurement - may need to use density equation to determine volume or mass - if you are looking for either mass or volume, put density over 1 and cross multiply and divide Systems D. Open and Closed Systems 1. Open System - a system that freely allows for the exchange of matter and energy 2. Closed System - a system that only allows for the free exchange of energy Systems B. Dynamic Equilibrium - a constantly shifting state of balance - Earth is essentially a closed system that operates under dynamic equilibrium Earth System Spheres - Earth can be viewed as an essentially closed system composed of several interacting spheres 1. Geosphere - all of the solid parts of Earth and the processes that involve them Earth Systems Spheres 2. Hydrosphere - all of the liquid water on Earth’s surface 3. Atmosphere - the layer of gases surrounding Earth 4. Biosphere - all of the living things on Earth Cycles - repeating patterns in nature - Ex.: tides, Moon phases, etc. 1. Water Cycle - movement of water between the four Earth spheres Cycles - involves the processes of: a. Precipitation - water falling out of Earth’s atmosphere b. Evaporation - when water goes from a liquid to gas in plants, water escapes from leaves transpiration - combination of evaporation and transpiration = evapotranspiration Cycles c. Runoff - water flowing over Earth’s surface d. Infiltration - water moving into the soil e. Condensation when water goes from a gas into a liquid Cycles 2. Carbon Cycle movement of carbon between the four spheres - involves the processes of: a. Photosynthesis - plants and phytoplankton remove carbon dioxide from the atmosphere Cycles b. Cellular Respiration when organisms take in carbohydrates and release carbon dioxide as a waste product c. Carbonization - when carbon compounds are formed in the oceans - oceans absorb about 40% of atmospheric carbon dioxide Cycles - carbonization also occurs in Earth’s crust through the formation of the mineral calcite, which is found in limestone and marble Cycles 3. Energy Cycle -exchange of energy through the Earth system amount of energy received by Earth equals the amount of energy lost by Earth Amount of energy gained compared to amount of energy lost = Earth’s energy budget Earth essentially functions as a black body - releases the same amount of energy that it gains on a daily basis Cycles a. Solar Energy - energy from the Sun - makes up 99.895% of all of Earth’s energy budget b. Geothermal Energy heat energy from Earth’s interior - makes up 0.013% of Earth’s energy budget Cycles c. Tidal Energy energy produced by the Moon and the Sun pulling on Earth - makes up 0.002% of Earth’s energy budget Cycles 3. Laws of Thermodynamics -- how energy moves through a system a. First Law of Thermodynamics energy can neither be created nor destroyed, it may only be transformed from one form to another (Law of Conservation of Energy) Cycles b. Second Law of Thermodynamics when energy is converted from one form to another, it is always changed from a more concentrated, more useful form to a less concentrated, less useful form Cycles 4. Albedo - how energy is reflected or absorbed by a surface - low albedo - little energy relfected (mostly absorbed) - Ex.: forest (5-10) - hIgh albedo - most energy reflected (little absorbed) - Ex.: snow bank (80) - Earth has an albedo of about 30 Scientific Inquiry - methodical system of problem solving - Involves the processes of: 1. Observing - recording data (information) from the environment - observations may be either qualitative (properties that are not easily measured) or quantitative (easily mesured with a measuring device) Scientific Inquiry 2. Asking Questions questions are usually based upon natural phenomena and require the use of experimentation in order to be answered 3. Hypothesizing formulating an educated guess that attempts to answer and/or explain the question Scientific Inquiry 4. Testing a Hypothesis tests and experiments are carried out in order to either support or refute a hypothesis 5. Sharing Results - after an experiment has been carried out, the results are frequently reported in a scientific journal - before a scientific paper may be published, it first must undergo peer review Scientific Inquiry - during peer review, experts in the field that the paper covers scrutinize the work of the scientist who wrote it - If the paper has merit, it is edited further and then possibly eventually printed Scientific Inquiry - If the paper is rejected, it mey be returned to the scientist with suggestions for revision and further study before it is ready for publishing Scientific Inquiry 5. Scientific Theories v. Scientific Laws - after a hypothesis has been supported many times, then it might be incorporated into a scientific theory - a scientific theory is an explanation for a natural event to which no exceptions have been currently found Scientific Theory - As new discoveries are made, a theory may be modified to incorporate that new knowledge - In science, a theory is not just “some idea” as the word is commonly used - Scientific theories have been proven to be reliable over a long period of time - Ex.: big bang theory Scientific Inquiry - scientific laws are generalizations about how the natural world behaves under certain conditions - scientific laws are NOT based on hypotheses - Scientific laws are discovered and there are never any exceptions to them Scientific Inquiry - Unlike theories, scientific laws may not be altered if new discoveries are made - Ex.: law of gravity