1. Chapter 2-1

2. The Experimental Method
Scientists make most of their discoveries using the experimental method.
This method consists of a series of steps

3. Observation
Observing is the first step of the experimental method.
Observations can take many forms, including descriptions, drawings, photographs, and measurements

4. Observation

5. Hypothesizing and Predicting
A hypothesis is a theory or explanation that is based on observations and that can be tested..

6. Hypothesizing and Predicting
Predictions are statements made in advance that express the results that will be obtained from testing a hypothesis if the hypothesis is supported.

7. Experimenting
Experiments are procedures that are carried out under controlled conditions to discover, demonstrate, or test a fact, theory, or general truth

8. Experimenting
The variable is the factor that changes in an experiment in order to test a hypothesis.

9. Independent Variable (IV) Dependent Variable (DV)
Experimenting
Independent Variable (IV)
Dependent Variable (DV)
The condition being studied
The condition being affected by the IV
Controlled by the researcher
Cannot be controlled by the researcher
Independent Variable Example
Dependent Variable Example
Cause
Effect
Before
After
Input
Output
What you do
What happens

10. Experimenting
The experimental group
The control group

11. Organizing and Analyzing Data
Organizing data into tables/graphs helps scientists analyze data and explain it data clearly
Graphs are often used by scientists to display relationships or trends in the data.

12. Organizing and Analyzing Data
Bar graphs are useful for comparing the data for several things in one graph.

13. Drawing Conclusions
Scientists determine the results of their experiment by analyzing their data and comparing the outcome of their experiments with their prediction.

14. Repeating Experiments
Scientists look for a large amount of supporting evidence before they accept a hypothesis.

15. The Correlation Method
Used when the use of experiments to answer questions is impossible or unethical
Correlation is the linear dependence between two variables.

16. The Correlation Method
Tree rings vs. Annual Rainfall

17. The Correlation Method
Why the settlers at Roanake Island all died

18. Scientific Habits of Mind
Curiosity
Skepticism
Openness to new ideas
Intellectual honesty
Share imagination and creativity

19. How Scientists use Statistics
Statistics is the collection and classification of data that are in the form of numbers
Analyzing and understanding data

20. How Scientists use Statistics
Mean:

21. How Scientists use Statistics
Distribution:

22. How Scientists use Statistics
A bell shaped curve indicates a normal distribution where the data is grouped symmetrically around the mean

23. What is the Probability?

24. What is RISK?
Risk is the probability of an unwanted outcome
What should we really worry about most?

25. Thinking about risk
Most people overestimate the risk of dying from sensational causes (plane crashes) vs. common causes (smoking).
Likewise, most citizens overestimate the risk of sensational environmental problems and underestimate the risk of ordinary ones.

26. Thinking about risk

27. Models
Models

28. Models
Physical Models & Graphical Models

29. Models
Conceptual models: verbal or graphical explanations for how a system works or is organized

30. Models
Mathematical models are one or more equations that represent the way system or process works.

32. “False color” satellite images are created using mathematical models.
Scientists use the models to relate the amount of energy reflected from objects to the objects’ physical condition.
Near infrared (red), green (blue), red (green). This is a traditional band combination useful in seeing changes in plant health.