Measurements and Calculations Scientific Method

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Preview Objectives Scientific Method Observing and Collecting Data Formulating Hypotheses Testing Hypotheses Theorizing Scientific Method Chapter 2

Objectives Describe the purpose of the scientific method. Distinguish between qualitative and quantitative observations. Describe the differences between hypotheses, theories, and models. Section 1 Scientific Method Chapter 2

Scientific Method The scientific method is a logical approach to solving problems by observing and collecting data, formulating hypotheses, testing hypotheses, and formulating theories that are supported by data. Let’s create a silly (but still tasteful) hypothesis to explore Section 1 Scientific Method Chapter 2

Observing and Collecting Data Observing is the use of the senses to obtain information. data may be qualitative (descriptive) quantitative (numerical) A system is a specific portion of matter in a given region of space that has been selected for study during an experiment or observation. Section 1 Scientific Method Chapter 2

Formulating Hypotheses Scientists make generalizations based on the data. Scientists use generalizations about the data to formulate a hypothesis, or testable statement. Hypotheses are often “if-then” statements. Section 1 Scientific Method Chapter 2

A hypothesis is an educated guess, based on observation. Usually, a hypothesis can be supported or refuted through experimentation or more observation. A hypothesis can be disproven, but not proven to be true.hypothesis Example: If you see no difference in the cleaning ability of various laundry detergents, you might hypothesize that cleaning effectiveness is not affected by which detergent you use. You can see this hypothesis can be disproven if a stain is removed by one detergent and not another. On the other hand, you cannot prove the hypothesis. Even if you never see a difference in the cleanliness of your clothes after trying a thousand detergents, there might be one you haven't tried that could be different.

Section 1 Scientific Method Chapter 2 What does this graphic tell us about the use of a phosphorus based fertilizer? Is there a limit to the effectiveness of a phosphorus based fertilizer?

Testing Hypotheses Testing a hypothesis requires experimentation that provides data to support or refute a hypothesis or theory. Controls are the experimental conditions that remain constant. Variables are any experimental conditions that change. Section 1 Scientific Method Chapter 2

Theorizing A model in science is more than a physical object; it is often an explanation of how phenomena occur and how data or events are related. visual, verbal, or mathematical example: atomic model of matter A theory is a broad generalization that explains a body of facts or phenomena. example: atomic theory Section 1 Scientific Method Chapter 2

A scientific theory summarizes a hypothesis or group of hypotheses that have been supported with repeated testing. A theory is valid as long as there is no evidence to dispute it. Therefore, theories can be disproven. Basically, if evidence accumulates to support a hypothesis, then the hypothesis can become accepted as a good explanation of a phenomenon. One definition of a theory is to say it's an accepted hypothesis.

Law A law generalizes a body of observations. At the time it is made, no exceptions have been found to a law. Scientific laws explain things, but they do not describe them. One way to tell a law and a theory apart is to ask if the description gives you a means to explain 'why'. Example: Consider Newton's Law of Gravity. Newton could use this law to predict the behavior of a dropped object, but he couldn't explain why it happened.

Scientific Method Section 1 Scientific Method Chapter 2

Preview Objectives Scientific Method Observing and Collecting Data Formulating Hypotheses Testing Hypotheses Theorizing Scientific Method Chapter 2