Presentation on theme: "Table of Contents Measurements and Calculations Section 1 Scientific Method Section 2 Units of Measure Section 3 Using Scientific Measurements Chapter."— Presentation transcript:
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. 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
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
Variables Variables are things that vary and change
Variables In any experiment there are 3 variables: an independent (or input) variable a dependent (or outcome) variable some control variables
Independent (input) variable This is the thing that you decide to change. You decide the time, so: time is the independent variable. Example Investigating how the rate of cooling of a beaker depends on the time.
Dependent (outcome) variable This is the variable that changes as a result. It is the variable that you measure. You measure the temperature every minute as it cools, so: temperature is the dependent variable. Example Investigating how the rate of cooling of a beaker depends on the time.
Control variables These are all the variables that must not change, to make sure it is a fair test. Example You must use the same beaker, with the same amount of water, in the same position in the room, at the same room temperature, so it is a fair test. Investigating how the rate of cooling of a beaker depends on the time.
When you draw up a table of your results, the independent variable goes in the first column, like this: Tables If you take several readings of the dependent variable, then you can calculate the mean (average) Then your results will be more reliable.
The independent variable is controlled by the scientist In Summary The dependent variable is ? what you measure in the experiment and what is affected during the experiment. The dependent variable responds to the independent variable. the same beaker, with the same amount of water, in the same position in the room, etc
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