Tools of Environmenta

l ScienceChapter 2

Objectives• List and describe the steps of the

experimental method.

• Describe why a good hypothesis is not simply a guess.

• Describe the two essential parts of a good experiment.

• Describe how scientists study subjects in which experiments are not possible.

• Explain the importance of curiosity and imagination in science.

Experimental Method - • a series of steps that scientists

worldwide use to identify and answer questions.

1)Observation

2)Hypothesis

3)Perform an experiment

4)Organize and analyze data

5)Draw conclusions

6)Repeat experiment

7)Communicate results

Experimental method begins when someone makes an observation and has a questions about what was observed.

Why are my plants wilting?

Experimental Method

Step #1: ObservationA piece of information we gather using

our senses – sight, hearing, smell, and touch

Can be represented withDescriptionsDrawingsPhotosMeasurement

Observations lead to questions

I see my plants bent over and turning brown. Why is my plant wilting?

Step #2: Form a Hypothesis

Hypothesis – a testable idea or explanation that leads to a scientific investigation

Used to answer a specific question about an observation

My plant is not getting enough water.

Step #3: Experiment

A procedure designed to test a hypothesis under controlled conditions

Should determine cause and effect relationships

I will water one plant on a regular basis and not water the one next to it.

Step #3: Experiments

In order to determine cause and effect experiments must have: A single variable that we are testing

Ex: water A control group - to serves as the

standard of comparison Ex: the plant with no water

Experimental group – condition with the new variable Ex: plant that gets water

• The independent, or manipulated variable, is a factor that’s intentionally changed by the experimenter.

• Ex: water

• The dependent, or responding variable, is the factor that may change as a result of changes made in the independent variable.

• Ex: health of the plant, degree of wilting

• All other factors and environmental conditions in the experiment must remain the same. They are the constants.

• Ex: soil, pot, room temperature

Step #3: Experiment

Step #4: Analyze Data

Data – gathered information, usually in a numeric form.

Data is put into graphs and tables for better understanding

Step #5: Conclusion

Determine the results of your study by analyzing their data and comparing the results with their predictions and hypothesis.

The plant that was watered did better than the one with no water.

Step #6: Repeat Experiment

Always repeat your experiement

WHY???

Step #7: Communicate results

Your study is not finished until you have shared your results

Correlation Method

When experimenting is unethical or impossible to test we can use correlations.

Correlation – an association between two or more events

Does not prove cause and effect relationships

Ex: There is a correlation between TV watching and childhood violence

Can you think of other reasons for this correlation?

Scientific State of Mind

Curiosity

Skepticism – don’t believe everything you are told

Openness to new ideas

Honesty

Imagination and creativity

Section 2 - Objectives

Explain how scientists use statistics.

Explain why the size of a statistical sample is important.

Describe three types of models commonly used by scientists.

Explain the relationship between probability and risk.

Explain the importance of conceptual models and mathematical models.

Section 2: Statistics and Models

Statistics – the collection and classification of data in the form of numbers

They help organize data by:SummarizingCharacterizingAnalyzingcomparing

Statistical Vocab

Mean – average

Probability – the chance that something will happen

Sample – a group selected to represent a larger population

Risk – the probability of an unwanted outcome

Distribution – shown on a graph

What are you afraid of?

Rank the following in order from mostly likely to die from to least likely: Venomous bite Airplane crash Drowning Cancer Car accident Falling down Gunshot Fireworks accident Heart disease Lightning

How did you do?

Heart disease 1 in 5

Cancer 1 in7

Car accident 1 in 100

Falling down 1 in 246

Gunshot 1 in 325

Drowning 1 in 8,942

Airplane crash 1 in 20,000

Lightning 1 in 83,930

Venomous Bite 1 in 100,000

Fireworks 1 in 615,488

Can you name some models?Not of the human type!

Models – representations of objects or systems

Physical models – three dimensional, you can touch them. Ex: globe

Graphical model – maps, charts, graphs

Conceptual model – a verbal or graphical explanation of how a system works or is organized. Ex: atom

Mathematical model – equations that represent the way a system or process works. Ex: earths rotation

Class Work

Ch. 2

Section 1 & 2 Review

Page 39 Questions: 1-4

Page 46 Questions: 1-3

Section 3 - Objectives

Describe three values that people consider when making decisions about the environment.

Describe the four steps in a simple environmental decision-making model.

Compare the short-term and long-term consequences of two decisions regarding a hypothetical environmental issue.

Section 3: Making Informed Decisions

Section 3: Making Informed Decisions

Decision-making model – a conceptual model that provides a systematic process for making decisions

Section 3: Making Informed Decisions

Read the Case Study-page 48-49 and answer questions

Section 3 review Pg. 51 # 1&2