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Scientific Method Concept Map What do we know about the scientific method? Build a concept map together as a class

Scientific Theories Scientific Theories The purpose of the scientific method is to establish scientific theories that can be used as predictive tools. A scientific theory is not a suspicion or a belief, but is defined by the National Academy of Sciences as a “well substantiated explanation of some aspect of the natural world that incorporates facts, laws, inferences and tested hypotheses” Ex. theory of evolution big bang theory

Other Explanations for Natural Processes Beliefs inspired by philosophy and theology Do not fit into the model and standards of the scientific method That is not to say that they lack value, but rather that the science classroom is not a place for their development

How did life originate on Earth?

Timeline for the Origin of Life 4.6 Bya: The Earth formed 3.9 Bya: End of heavy bombardment of Earth with ice and rock ??: The origin of life 3.5 Bya: Earliest fossil evidence of life Stromatolites

Earth’s Early Atmosphere Mostly water vapor (H2O), nitrogen (N2), and carbon dioxide (CO2) Small amounts of hydrogen (H2), methane (CH4), ammonia (NH3), hydrogen sulfide (H2S), and carbon monoxide (CO) Very little oxygen (O2)

In order for there to be life, you need… Synthesis of simple organic (carbon-based molecules that make up living things) molecules from inorganic molecules Assembly of these small molecules into larger macromolecules (ex. proteins and nucleic acids) Packaging of these macromolecules into cell-like structures The ability to self-replicate 1 3 2

The “Organic Soup” Model The conditions of the early atmosphere allowed chemical reactions which formed simple organic molecules from atmospheric gases An energy input was required Lightning or UV radiation Organic molecules then dissolved in the oceans

What would count as evidence of a model of the “Organic Soup” Model? A scientific model = “The generation of a physical, conceptual, or mathmatical representation of a real phenomenon that is difficult to observe directly” Encyclopaedia Britannica