1. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Scientific Method Observation Hypothesis - an explanation based on observations and can be tested. –Predictions - statements made in advance Experiments Chapter 2 Section 1 Scientific Methods

2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Experimenting Good experiments have: –a single variable - the factor that changes in an experiment –2 groups experimental group - receives the variable. control group - comparison to the experimental group. Chapter 2 Section 1 Scientific Methods

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Organizing and Analyzing Data Data - pieces of information from observation or experimentation. Organizing data into tables /graphs helps scientists analyze and explain the data Graphs display relationships or trends. Chapter 2 Section 1 Scientific Methods

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Drawing Conclusions Scientists determine the results by comparing the outcome with their hypothesis. The more an experiment can be repeated with the same results, by different people, the more conclusive it is. Scientists publish their results to share what they have learned with other scientists. Chapter 2 Section 1 Scientific Methods

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu The Correlation Method Correlation is the linear dependence between two variables. Example: the width of a tree ring is a good indicator of the rainfall the tree received that year. Chapter 2 Section 1 Scientific Methods

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Scientific Habits of Mind Curiosity skepticism openness to new ideas intellectual honesty Imagination and creativity Chapter 2 Section 1 Scientific Methods

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu How Scientists use Statistics Statistics -collection and classification of numerical data. mean - average –provides a single measure for comparison. Probability - likelihood that a possible future event will occur Chapter 2 Section 2 Statistics and Models

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Distribution Distribution - arrangement of the statistics of a population. The graphs of many characteristics form bell-shaped curves (ex: height, income). –data is grouped symmetrically around the mean. Chapter 2 Section 2 Statistics and Models

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Thinking About Risk Risk is the probability of an unwanted outcome. Chapter 2 Section 2 Statistics and Models

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Models Models show the structure or workings of an object, system or concept. Physical Models –3D models –resemble the object they represent, but may be larger or smaller. Chapter 2 Section 2 Statistics and Models

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Graphical Models Maps and charts Chapter 2 Section 2 Statistics and Models

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Conceptual Models Conceptual models - how a system works or is organized. A flow-chart illustrates what a system contains, how those contents are organized and affect one another. Chapter 2 Section 2 Statistics and Models

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Mathematical Models Mathematical models are equations that represent the way system or process works. Mathematical models are useful in cases which may be variable Chapter 2 Section 2 Statistics and Models

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Values and the Environment Values - principles that an individual considers important. Chapter 2 Section 3 Making Informed Decisions

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu An Environmental Decision-Making Model decision-making model - conceptual model that provides a systematic process for making decisions. –used to make decisions about difficult environmental issues. Chapter 2 Section 3 Making Informed Decisions

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu A Hypothetical Situation (do not write) The golden-cheeked warbler population is declining in Valley County. The town of Pleasanton, in Valley County, is growing rapidly, and much of the new development is occurring outside the city limits. Biologists who have been studying the warbler warn county officials that if they do not take action, the state fish and wildlife service may list the bird as an endangered species. Chapter 2 Section 3 Making Informed Decisions

17. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu A Hypothetical Situation (do not write) Several groups join together to propose that the county buy several hundred acres of land where the birds are known to breed and save the land as a nature preserve. Chapter 2 Section 3 Making Informed Decisions

18. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu A Hypothetical Situation (do not write) The group also proposes limiting development on land surrounding the preserve. The group obtains enough petitions to put the issue to a vote, and the public begins to discuss the proposal. Chapter 2 Section 3 Making Informed Decisions

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu A Hypothetical Situation (do not write) People who own property within the proposed preserve oppose the plan. These property owners have an economic interest in the situation. They believe that they will lose money if they are forced to sell their land to the county instead of developing it. Other residents do not like the idea of more government regulations on how private property can be used. Chapter 2 Section 3 Making Informed Decisions

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu A Hypothetical Situation (do not write) Other landowners support the plan and fear that without the preserve the warbler will be listed as an endangered species. Once listed as endangered, the state will impose a plan to protect the bird that will require even stricter limits on land development. People who have land near the preserve think that their land will increase in value. Many residents also look forward to hiking and camping in the preserve. Chapter 2 Section 3 Making Informed Decisions

21. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Your turn to discuss: –Gather information-what is the problem? –Consider Values-what are yours? –Explore consequences-what are negative outcomes (short and long term)? –Make a decision-what would you do?

22. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 2 Section 3 Making Informed Decisions

23. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Make a Decision As you learn about issues affecting the environments, use this decision-making model. Be sure to: –consider your values –weigh the pros and cons –keep in mind both the short-term and long-term consequences of your decision. Chapter 2 Section 3 Making Informed Decisions