Biology and YouSection 2 Section 2: Scientific Methods Preview Bellringer Key Ideas Beginning a Scientific Investigation Scientific Experiments Scientific Theories Summary

Biology and YouSection 2 Bellringer Imagine that all of the birds around the school are dying. How might you investigate the problem? Write a brief description of your investigation. Which stages of a scientific investigation are represented in your answer?

Biology and YouSection 2 Key Ideas How do scientific investigations begin? What are two methods scientists can use to test hypotheses? What is the difference between a theory and a hypothesis?

Biology and YouSection 2 Beginning a Scientific Investigation Most scientific investigations begin with observations that lead to questions. _____________ is the act of noting or perceiving objects or events using the senses. To answer a question, scientists first _______________ a hypothesis that leads to scientific investigation. A ________________ is a possible explanation that can be tested by observation or experimentation.

Biology and YouSection 2 Visual Concept: Hypothesis

Biology and YouSection 2 Scientific Experiments An experiment is a procedure that is carried out under controlled conditions to test a hypothesis. A controlled experiment tests one factor at a time and uses a control group and an experimental group. A ___________ group is a group that serves as a standard for comparison in an experiment. The experimental groups are identical to the control group except for one factor, called a ____________.

Biology and YouSection 2 Scientific Experiments, continued The single factor that scientists change in an experiment is called the ____________ ____________. Factors that may change in response to the independent variable are called _____________ variables. Scientists analyze changes to the dependent variables in order to understand how the independent variable affects the system that they are studying.

Biology and YouSection 2 Visual Concept: Controlled Experiment and Variable

Biology and YouSection 2 Visual Concept: Independent and Dependent Variables

Biology and YouSection 2 Scientific Experiments, continued There are often cases in which experiments are not possible or not _____________. In these cases, researchers perform __________. In a study, researchers gather data about a system by making ____________ rather than by manipulating independent variables.

Biology and YouSection 2 Scientific Experiments, continued After conducting an experiment, researchers ___________ their results to learn whether the results support their hypothesis or not. Scientists draw __________ that explain the results of their experiments. Scientists verify their conclusions by conducting their experiments _______ _________and by checking to see if other scientists have found similar results.

Biology and YouSection 2 Visual Concept: Scientific Method

Biology and YouSection 2 Scientific Experiments, continued Every person has his or her own _________ __ _______. A particular point of view is called a _______. Scientists try to prevent bias from affecting their work, but bias can still influence an experiment. Sources of funding, personal involvement in a product, and other conflicts of interest can affect an experiment. It is wise to view all scientific claims in their context and _______ _____________about them.

Biology and YouSection 2 Scientific Theories In science, a ___________ is a system of ideas that explains many related observations and is supported by a large body of _____________. The main difference between a theory and a hypothesis is that a hypothesis is a _________, testable prediction for a limited set of conditions and a theory is a general explanation for a broad range of data. Constructing a theory often involves considering contrasting ideas and _____________ hypotheses.

Biology and YouSection 2 Scientific Theories, continued If the results of a scientific experiment can be reproduced many times, the research may help develop a ______ ___________. Future research may cause a theory to be ________ or even ___________. By investigating and _____________ theories, scientific understanding grows.

Biology and YouSection 2 Summary Most scientific investigations begin with ____________ that lead to ____________. Scientists can conduct controlled experiments and perform studies in order to _________ a hypothesis. The main difference between a theory and a hypothesis is that a hypothesis is a specific, ____________ prediction for a limited set of conditions, while a theory is a ___________ ______________for a broad range of data.