Section 2 Scientific Methods Scientists use scientific methods

Section 2: Scientific Methods Scientists use scientific methods to systematically pose and test solutions to questions and assess the results of the tests. K What I Know W What I Want to Find Out L What I Learned

• 2(C) Know that scientific theories are based on natural and physical phenomena and are capable of being tested by multiple independent researchers. Unlike hypotheses, scientific theories are well– established and highly–reliable explanations, but may be subject to change as new areas of science and new technologies are developed. • 2(B) Know that scientific hypotheses are tentative and testable statements that must be capable of being supported or not supported by observational evidence. Hypotheses of durable explanatory power which have been tested over a wide variety of conditions are incorporated into theories. • 2(D) Distinguish between scientific hypotheses and scientific theories. Copyright © Mc. Graw-Hill Education Scientific Methods

• • 2(E) Plan and implement investigative procedures, including asking questions, formulating testable hypotheses, and selecting equipment and technology, including graphing calculators, computers and probes, sufficient scientific glassware such as beakers, Erlenmeyer flasks, pipettes, graduated cylinders, volumetric flasks, safety goggles, and burettes, electronic balances, and an adequate supply of consumable chemicals 2(H) Organize, analyze, evaluate, make inferences, and predict trends from data. 2(I) Communicate valid conclusions supported by the data through methods such as lab reports, labeled drawings, graphs, journals, summaries, oral reports, and technology–based reports. 3(A) In all fields of science, analyze, evaluate, and critique scientific explanations by using empirical evidence, logical reasoning, and experimental and observational testing, including examining all sides of scientific evidence of those scientific explanations, so as to encourage critical thinking by the student. Copyright © Mc. Graw-Hill Education Scientific Methods

Essential Questions • What are the common steps of scientific methods? • What are the variables and the controls in an experiment? • What is the difference between a scientific theory and a scientific law? Copyright © Mc. Graw-Hill Education Scientific Methods

Vocabulary Review New • systematic approach • • New • • scientific method qualitative data quantitative data hypothesis Copyright © Mc. Graw-Hill Education experiment independent variable control conclusion scientific theory scientific law Scientific Methods

A Systematic Approach The scientific method is a systematic approach used in scientific study, whether it is chemistry, physics, biology, or another science. It is an organized process used by scientists to do research, and provides methods for scientists to verify the work of others. The steps in a scientific method are repeated until a hypothesis is supported or discarded. Copyright © Mc. Graw-Hill Education Scientific Methods

A Systematic Approach An observation is the act of gathering information. • Qualitative data is obtained through observations that describe color, smell, shape, or some other physical characteristic that is related to the five senses. • Quantitative data is obtained from numerical observations that describe how much, how little, how big or how fast. A hypothesis is a tentative explanation for what has been observed. An experiment is a set of controlled observations that test the hypothesis. Copyright © Mc. Graw-Hill Education Scientific Methods

A Systematic Approach A variable is a quantity or condition that can have more than one value. • An independent variable is the variable you plan to change. • The dependent variable is the variable that changes in value in response to a change in the independent variable. If you were trying to determine if temperature affects bacterial growth, you would expose different petri dishes of the same bacteria to different temperatures. • Temperature is your independent variable. • Bacteria growth is your dependent variable. Copyright © Mc. Graw-Hill Education Scientific Methods

A Systematic Approach A control is a standard for comparison in the experiment. • During clinical drug trials, physicians will use a double-blind study. They use two statistically identical groups of patients. One will receive the drug and one will receive a placebo. Neither patient or physician will know which group receives the drug. • The group receiving the placebo is the control group. A conclusion is a judgment based on the information obtained from the experiment. • A hypothesis is never proven, only supported or discarded. Copyright © Mc. Graw-Hill Education Scientific Methods

Theory and Scientific Law A scientific theory is an explanation that has been repeatedly supported by many experiments. • A theory states a broad principle of nature that has been supported over time by repeated testing. • Theories are successful if they can be used to make predictions that are true. A scientific law is a relationship in nature that is supported by many experiments, and no exceptions to these relationships are found. Copyright © Mc. Graw-Hill Education Scientific Methods

Review Essential Questions • Why do elements in the same group have similar properties? • Based on their electron configurations, what are the four blocks of the periodic table? Vocabulary • • scientific method qualitative data quantitative data hypothesis Copyright © Mc. Graw-Hill Education • experiment • independent variable • dependent variable • • control conclusion scientific theory scientific law Scientific Methods