Scientific Thinking

Body Of Knowledge - Nature of ScienceBig Idea 1 – The Practice of ScienceBig Idea 2 – The Characteristics of Scientific KnowledgeBig 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. 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 sciencePhysicists

Biologi

st

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 TectonicsEvidence – 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

Newton’s Laws of Motion

Universal Law of Gravitation

Law of Conservation of Energy

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 EvolutionAll 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

Benefits•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 encounteredSC.8.N.3.2 – Explain why theories may be modified but are rarely discarded

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!

Germ Theory (1870s) – specific microorganisms are the causes of specific diseases

Louis Pasteur demonstrated that microbes decomposedmeat and heat killsbacteria

Robert Kochdemonstrated that specific diseases werecaused by specific germs

SC.7.N.1.2 – Differentiate replication (by others) from repetition (multiple trials)

Trial Numb

er

Height after 5 Days (cm)

1 30

2 31

3 30

4 30.5

5 31

AVE 30.5

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.

Table 1: Plant Growth with TurboGro by Trial

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

HypothesisIf 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.DiscussionIn 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.

EXAMPLE

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