Body Of Knowledge - Nature of Science Scientific Thinking Body Of Knowledge - Nature of Science Big Idea 1 – The Practice of Science Big Idea 2 – The Characteristics of Scientific Knowledge Big Idea 3 – The Role of Theories, Laws, Hypotheses, and Models

SC.8.N.2.2 – Discuss what characterizes science and its methods Science is a way of understanding the natural world around us. It is based upon the idea that our senses, and extensions of our senses through instrumentation/technology, give us accurate information about the natural world. Scientists ask, “What is there? How does it work? How did it come to be this way?

The joy of science is in the freedom to explore and wonder Science relies on evidence and creativity

Science explanations are evaluated by testing and using evidence Science explanations are evaluated by testing and using evidence. Explanations that don’t fit evidence are rejected or modified and tested again. Science claims are subject to peer review and replication. Scientists attempt to identify alternate explanations to get closest to the truth.

There is NO one “Scientific Method”! Scientists continually make observations, question, and form multiple hypotheses. http://evolution.berkeley.edu/evosite/nature/IIprocess3.shtml Science never “proves.” Hypotheses are either “supported” or “not supported” by the data collected.

SC.6.N.1.5 – Recognize that science involves creativity, not just in designing experiments, but also in creating explanations that fit evidence Dinosaur Extinction Hypotheses: Asteroid? Volcanism? Climate Change?

SC.8.N.1.5 – Analyze the methods used to develop a scientific explanation as seen in different fields of science Physicists Biologist Volcanologist Geologists Chemists

SC.7.N.1.6 – Explain that empirical evidence is the cumulative body of observations of a natural phenomenon (event) on which scientific explanations are based

SC.7.N.1.7 – Explain that scientific knowledge is the result of a great deal of debate and confirmation within the science community Science Conferences

SC.8.N.1.6 – Understand that scientific investigations involve the collection of relevant empirical evidence, the use of logical reasoning, and the application of imagination in devising hypotheses, predictions, explanations, and models to make sense of collected evidence

SC.6.N.3.1 – Recognize and explain that a scientific theory is a well supported and widely accepted explanation of nature and is not simply a claim posed by an individual. The Theory of Plate Tectonics Evidence – Sea Floor Spreading, Distribution of earthquakes and volcanoes, Fossils Claim – Volcanoes erupt in Hawaii because of Pele, the goddess of fire

SC.6.N.3.2 – Recognize and explain that a scientific law is a description of a specific relationship under given conditions in the natural world (different from societal laws). Newton’s Laws of Motion

SC.6.N.3.3 – Give several examples of scientific laws Law of Conservation of Energy Newton’s Laws of Motion Universal Law of Gravitation Law of Conservation of Mass

SC.7.N.3.1 – Recognize and explain the difference between theories and laws and give several examples of scientific theories and the evidence that supports them THEORY Explanation based upon evidence Verified multiple times Can be used to make predictions LAW A statement that describes an action or set of actions Can be expressed as a mathematical equation Simple, true, universal Theories explain WHY something happens Laws describe WHAT happens

Theory Example – The Theory of Biological Evolution All life on Earth shares a common ancestor. There is “decent with modification.” Evidence – Fossil Record, Genetic Studies, Radiometric Dating, Stratigraphy The horse’s foot adapted to a changing climate http://www.sepa.duq.edu/darwin/education-tools-horseFeet_new.shtml

SC.6.N.3.4 – Identify the role of models. Model – a representation of an object, process, system, or event that is similar to the original object or idea role – models help scientists better understand objects/ideas; allow hands-on contact with matter that is too small, too large, too far away, too dangerous, or too expensive to build

SC.7.N.3.2 – Identify the benefits and limitations of the use of scientific models Used to study matter that is too large, too small, too far away, too dangerous, or too expensive to study directly Models can be physical, mathematical, computer simulations, or conceptual Can be used to make predictions Limitations May lack details May not be composed of the original material (model of the Sun) May not be able to demonstrate every aspect of the system

SC.6.N.2.2 – Explain that scientific knowledge is durable because it is open to change as new evidence or interpretations are encountered SC.8.N.3.2 – Explain why theories may be modified but are rarely discarded Germ Theory (1870s) – specific microorganisms are the causes of specific diseases Louis Pasteur demonstrated that microbes decomposed meat and heat kills bacteria Robert Koch specific diseases were caused by specific germs Miasma - Before the 1800s, it was thought that diseases were caused by miasma, a poisonous vapor in the air filled with particles of decaying matter!

SC.7.N.1.2 – Differentiate replication (by others) from repetition (multiple trials) Table 1: Plant Growth with TurboGro by Trial Trial Number Height after 5 Days (cm) 1 30 2 31 3 4 30.5 5 AVE Dr. Square copied Dr. Groovy’s procedure and got similar results! The plants grew an average of 30 cm in 5 days! If scientific explanations are replicable, they are more valid and reliable. SC.6.N.1.2 – Explain why scientific explanations should be replicable

SC.8.N.1.3 – Use phrases such as “results support” or “fail to support” in science, understanding that science does not offer conclusive “proof” of a knowledge claim EXAMPLE Hypothesis If Turritella snail fossils are compared for height and number/location of predation drill holes, then there will be an escape size where the holes are absent, because the predators in the community would no longer be large enough to feed on the snails. Discussion In the study area, predation drill holes are absent on Turritella over 6 cm. The results support the hypothesis. The researcher infers that once Turritella grew to 6 cm in length, it escaped predation. There is NO conclusive proof of this claim, as this is one study conducted in one particular study area.

SC.8.N.1.4 – Explain how hypotheses are valuable if they lead to further investigations, even if they turn out not to be supported by the data Studies that analyze the strengths and weaknesses of alternative explanations are valuable. They encourage others to more thoroughly examine the ideas and evidence and to develop new ways to test the ideas.

SC.6.N.1.3 – Explain the difference between an experiment and other types of scientific investigation, and explain the relative benefits and limitations of each SC.7.N.1.3 – Distinguish between an experiment and other forms of scientific investigation and explain that not all scientific knowledge is derived from experimentation Experiment – involves identification and control of variables Independent variable/test variable/manipulated variable Dependent variable/outcome variable/responding variable Controlled variables Field Study – observe a natural habitat without manipulating variables Simulation – imitating a real situation or process

SC.7.N.1.4 – Identify test variables (independent variables) and outcome variables (dependent variables) in an experiment Independent Variable (Test Variable): the amount of light per day Dependent Variable (Outcome Variable): plant growth measured in cm