Unit 1 Lesson 2 Scientific Investigations

Unit 1 Lesson 2 Scientific Investigations Testing, Testing, 1, 2, 3 What are some parts that make up scientific investigations? Scientists investigate the natural world through experiments and observations. An experiment is an organized procedure to study something under controlled conditions. Observation is the process of obtaining information by using the senses. Copyright © Houghton Mifflin Harcourt Publishing Company 2

What are some parts that make up scientific investigations? Unit 1 Lesson 2 Scientific Investigations What are some parts that make up scientific investigations? Scientific investigations may also involve the use of models. A model is a representation of an object or a system. Copyright © Houghton Mifflin Harcourt Publishing Company 3

What are some parts that make up scientific investigations? Unit 1 Lesson 2 Scientific Investigations What are some parts that make up scientific investigations? A hypothesis is a testable idea or explanation that leads to scientific investigation. A scientist may think of a hypothesis after making observations or after reading findings from other scientists’ investigations. Hypotheses must be carefully constructed so they can be tested in a practical and meaningful way. Copyright © Houghton Mifflin Harcourt Publishing Company 4

What are some parts that make up scientific investigations? Unit 1 Lesson 2 Scientific Investigations What are some parts that make up scientific investigations? If an investigation does not support a hypothesis, it is still useful. The information from the investigation can help scientists form a better hypothesis. Scientists may go through many cycles of testing and analysis before they arrive at a hypothesis that is supported. Copyright © Houghton Mifflin Harcourt Publishing Company 5

What are some parts that make up scientific investigations? Unit 1 Lesson 2 Scientific Investigations What are some parts that make up scientific investigations? A variable is any factor that can change in a scientific investigation. An independent variable is the factor that is deliberately manipulated. A dependent variable changes as a result of manipulation of one or more independent variables. Copyright © Houghton Mifflin Harcourt Publishing Company 6

What are some parts that make up scientific investigations? Unit 1 Lesson 2 Scientific Investigations What are some parts that make up scientific investigations? Data are information gathered by observation or experimentation that can be used in calculating or reasoning. This information may be anything that a scientist perceives through the senses or detects using instruments. During their investigations, scientists record all their observations, setup, and procedures, so that they will not forget anything. Copyright © Houghton Mifflin Harcourt Publishing Company 7

What are some parts that make up scientific investigations? Unit 1 Lesson 2 Scientific Investigations What are some parts that make up scientific investigations? Scientists analyze data to determine the relationship between the independent and dependent variables in an investigation. Then they draw conclusions about whether the data support the investigation’s hypothesis. Copyright © Houghton Mifflin Harcourt Publishing Company 8

Many Methods What are some scientific methods? Unit 1 Lesson 2 Scientific Investigations Many Methods What are some scientific methods? Scientists do not always use the same steps or same order of steps in every investigation. They may even repeat some steps. Copyright © Houghton Mifflin Harcourt Publishing Company 9

What are some scientific methods? Unit 1 Lesson 2 Scientific Investigations What are some scientific methods? Consider one possible path that a scientist might follow while conducting an experiment. First, the scientist clearly and precisely defines the problem or question that needs to be answered. Next, the scientist forms a hypothesis and makes predictions about what will happen in the investigation. Copyright © Houghton Mifflin Harcourt Publishing Company 10

What are some scientific methods? Unit 1 Lesson 2 Scientific Investigations What are some scientific methods? To test the hypothesis, the investigation must be carefully planned, taking into account the materials and equipment needed. The scientist must also decide how the independent variable will change and identify other variables that will be controlled. Copyright © Houghton Mifflin Harcourt Publishing Company 11

What are some scientific methods? Unit 1 Lesson 2 Scientific Investigations What are some scientific methods? The scientist must also determine how the results of the experiment will be measured. The data collected in an investigation must be recorded and properly organized. After the data are collected, the scientist needs to analyze the information and draw conclusions about the results. Copyright © Houghton Mifflin Harcourt Publishing Company 12

What are some scientific methods? Unit 1 Lesson 2 Scientific Investigations What are some scientific methods? If the hypothesis is not supported, the scientist may think about the problem some more and come up with a new hypothesis to test. An experiment may need to be repeated to check for mistakes. When publishing the results of their investigation, scientists must be prepared to defend their conclusions. Copyright © Houghton Mifflin Harcourt Publishing Company 13

Life Lessons How are scientific methods used? Unit 1 Lesson 2 Scientific Investigations Life Lessons How are scientific methods used? Scientific methods are used in physical, life, and Earth sciences. Scientists carefully choose the setting for an investigation, such as whether to work in the field or in a laboratory. Scientists may use models when studying things that are very large, very small, or occurring over a long period of time. Copyright © Houghton Mifflin Harcourt Publishing Company 14

Unit 1 Lesson 2 Scientific Investigations High Quality What are some characteristics of good scientific investigations? Good scientific investigations share some important characteristics. Scientific observations should be well-documented and have supporting evidence. In an experiment, the variables should be controlled as much as possible. Copyright © Houghton Mifflin Harcourt Publishing Company 15

What are some characteristics of good scientific investigations? Unit 1 Lesson 2 Scientific Investigations What are some characteristics of good scientific investigations? Experiments should be repeated multiple times by the original investigator. Scientific investigations should also be able to be replicated by scientists not involved with the original work. Before publishing a study, scientific journals ask other scientists to review the article. This is called peer review. Copyright © Houghton Mifflin Harcourt Publishing Company 16

What are some characteristics of good scientific investigations? Unit 1 Lesson 2 Scientific Investigations What are some characteristics of good scientific investigations? How might a scientist test the hypothesis that objects of different masses fall at the same rate? Copyright © Houghton Mifflin Harcourt Publishing Company 17

How can you evaluate the quality of scientific information? Unit 1 Lesson 2 Scientific Investigations How can you evaluate the quality of scientific information? The most reliable scientific information is published in scientific journals, but it is often difficult to understand. Reliable books are written by scientists and others who are knowledgeable about a particular field. Reliable Internet sources are government and academic web pages. Commercial web pages are often unreliable because they are trying to sell something. Copyright © Houghton Mifflin Harcourt Publishing Company 18