1. Chapter 2: Tools of Environmental Science
Cherokee High School
Environmental Science
Mrs. Toner

2. The Scientific Method Also known as the experimental method.
It is a series of steps that scientists all over the world use to identify and answer questions.
The first step is observation – information we gather using our senses (sight, touch, hearing, smell).
What kinds of tools do scientists use to observe?
Observations can be in the form of descriptions, drawings, photographs, and measurements.
Tools used to observe: microscope, ruler, satellites.

3. Tools Scientists Use to Observe

4. The Scientific Method (continued)
Observations lead to questions. To answer a specific question, a scientist may form a…..
Hypothesis – a testable idea which leads to an experiment (or scientific investigation).
A hypothesis is more than a guess! Often, it is based on what you already know.
See handout on Dwarf Wedge Mussels.
To test their hypothesis, the students made a prediction which is a logical statement about what will happen if the hypothesis is correct.

5. The Scientific Method (continued)
Experiment – a procedure designed to test a hypothesis under controlled conditions.
Experiments must be designed to pinpoint cause-and-effect relationships. So, a single variable is tested and a control is used.
Scientists usually study two groups at a time:
The group that receives the experimental treatment is called the experimental group.
The group that doesn’t receive the experimental treatment is called the control group.
The variable is the single factor of interest and it is the only difference between the experimental group and the control group.

6. The Scientific Method (continued)
Collecting data – the information a scientist gathers during an experiment which is usually in numerical form.
Scientists organize their data into tables, charts, and/or graphs. This makes it easier for them to communicate their findings to others.

7. The Scientific Method (continued)
Reaching a conclusion –
Scientists study their data to determine the results from their experiment.
Scientists compare the outcome of their experiment to their prediction.
A conclusion is made.
Often, experiments are repeated to see if the results are reliable.

8. The Scientific Method:
Observation
Question
Analyze Data
Conclusion

9. Scientific Habits of Mind
Good scientists share some key “habits of mind” or ways of approaching or thinking about things:
Curiosity – a genuine interest in a subject leads to wanting to learn more about it.
The Habit of Skepticism – not believing everything you are told.
Openness to New Ideas – keeping an open mind as to how the world works.
Intellectual Honesty - being honest about your results
Imagination and Creativity – ability to conceive new ideas, see patterns that others cannot, or to imagine things others cannot.

10. What’s the difference between a hypothesis and a prediction?
A hypothesis is a testable idea that leads to an experiment.
A prediction is a logical statement about what will happen if the hypothesis is correct.
For example, the Keene High School students hypothesized that phosphate fertilizers from lawns were washing into the river and killing the mussels.
The students may have predicted that mussels will die when exposed to high levels of phosphate in the water.

11. Making Correlations
Scientists study questions by doing experiments. But what if an experiment can’t be done?
Scientists can test predictions by examining correlations – associations between two or more events.
The width of rings in a tree trunk indicate the amount of rainfall the tree received in a given year. Trees produce wide rings in rainy years and narrow rings in dry years.
Scientists used this information to investigate why most of the first settlers at Jamestown, VA died.
The rings of very old trees on the Virginia coast indicate that the Jamestown colony was founded during one of the worst droughts ever recorded. The settlers most likely died from starvation as a result of not being able to farm.

12. Rings of a Tree Trunk Can be Used to Make Correlations:

13. Students at Keene High School Study Dwarf Wedge Mussels
1. The students have observed that____________.
2. The students also have observed that the______ is __________.
3. These observations prompted the students to take the next step in the experimental method - __________ a ____________.
4. What two trends did the students notice?
5. When students tested the water, what did they find?
6. What are phosphates?
7. How might phosphates end up in the water?
8. What was the prediction the students made?
9. What is the difference between a hypothesis and a prediction?
Read the “Case Study” on page 35 and answer the following questions:
1. Explain what students placed into each of the two tanks.
2. What 4 things were to be constant (identical) when setting the tanks up?
3. What did the students do to the experimental group?
4. What did they do to the control group?
5. What does replication mean and how could the students replicate their experiment?

14. Review of Chapter 2, Section 1:
1. Describe the steps of the experimental method.
2. Name three scientific habits of mind and explain their importance.
3. Explain why a hypothesis is not just a guess.
Vocabulary Words:
observation
hypothesis
prediction
experiment
variable
experimental group
control group
data
correlation

15. Statistics and Models
Scientists generate a lot of data which needs to be organized.
Statistics is the collection and organization of data that are in the form of numbers.
Used to summarize, characterize, analyze and compare data.
Some terms – mean, distribution, probability, sample

16. What’s the Average?
The mean is the number obtained by adding the data for a characteristic and dividing this sum by the number of individuals (average).
The mean provides a single measure for a given characteristic of a population.
Find the mean for the following data set:
12, 25, 32, 6
= 75
75/4 = 18.75

17. The Distribution
A distribution is the relative arrangement of the members of a statistical population (see pg. 41, figure 9).
The lengths of the individuals are arranged between 15 and 50.
The overall shape of the bars is also part of the distribution.
Notice the bell-shaped curve. A bell-shaped curve represents a normal distribution.

18. What is the Probability
Probability – the chance that something will happen.
What’s the probability that if you toss a coin it will come up heads?
Usually expressed as a decimal between 0 and 1:
Suppose a quarter comes up heads 7 out of 10 times.
7/10 = 0.7 Is this 50/50? No! What’s the problem? The problem is that the sample size is too small to give an accurate result.
Sample – a group of individuals or events selected to represent the population.
What’s the sample size if you toss a coin 10 times?
What’s the sample size if you toss the coin 1,000 times? We are almost certain to see heads 50% of the time and tails 50% of the time with a sample size this large.

19. Risk Risk – the probability of an unwanted outcome.
Example - 60% chance of rain today. What is the risk that it will rain?
Example – if you have a 1 in 4 chance of failing a class, the risk of failing is ¼, or 0.25.

20. Models Models are representations of objects or systems.
Physical Models
Graphical Models
Conceptual Models
Mathematical Models

21. Physical Models
Physical Models are three-dimensional models you can touch.
The most useful models teach scientists something new and help to further other discoveries.
Example – the structure of DNA (pg 44, figure 12).

22. Graphical Models Maps and charts (pg 44, fig. 13)
Graphical models are used to show things like the position of stars, the amount of forest cover in an area, or the depth of water along a coast.

23. Conceptual Model
A conceptual model – a verbal or graphical explanation of how a system works or is organized.
A flow chart diagram is an example.
See page 45, fig. 14.

24. Mathematical Models
A mathematical model is one or more equations that represents the way a system works.

25. Chapt. 2, Section 2 Vocabulary (text book pages 40-46)
Statistics
Mean
Distribution
Probability
Sample
Risk
Model
Physical model
Graphical model
Conceptual model
Mathematical model

26. 2.3 – Making Informed Decisions
Scientific research is the first step to solving environmental problems.
Many factors must be considered before decisions can be made about solutions:
How will people’s lives be affected?
How much will it cost?
Is the solution ethical?
Questions like the ones above require an examination of values.

27. What are values? Values are moral principles we consider important.
Which values should influence decisions we make about our environment?
Economic – the gain or loss of money or jobs
Environmental – the protection of natural resources
Ethical/moral – what is right or wrong
Health – the maintenance of human wellbeing
Social/cultural – maintaining human communities, their values and traditions

28. An Environmental Decision-Making Model
A decision-making model is a conceptual model that provides a systematic process for making decisions.
Gather Information
Consider Values
First step is to gather info. – watch the news, read about the issue, talk with well-informed people on all sides of the issue.
Then, consider which values apply to the issue.
Explore the consequences of each option.
Evaluate all of the information in order to make the BEST decision.
Explore Consequences
Make a Decision