Chapter 2: Tools Chapter 2: Tools of Environmental of Environmental

ScienceScienceCherokee High SchoolCherokee High School

Environmental ScienceEnvironmental Science

Mrs. TonerMrs. Toner

The Scientific MethodThe Scientific Method Also known as the Also known as the experimental method.experimental method. It is a series of steps that scientists all over It is a series of steps that scientists all over

the world use to identify and answer the world use to identify and answer questions.questions.

The first step is The first step is observation – observation – information information we gather using our senses (sight, touch, we gather using our senses (sight, touch, hearing, smell). hearing, smell). What kinds of tools do scientists use to observe?What kinds of tools do scientists use to observe? Observations can be in the form of descriptions, Observations can be in the form of descriptions,

drawings, photographs, and measurements.drawings, photographs, and measurements.

Tools Scientists Use to Tools Scientists Use to ObserveObserve

The Scientific Method The Scientific Method (continued)(continued)

Observations lead to Observations lead to questionsquestions. To . To answer a specific question, a scientist answer a specific question, a scientist may form a…..may form a…..

HypothesisHypothesis – a testable idea which leads – a testable idea which leads to an experiment (or scientific to an experiment (or scientific investigation).investigation). A hypothesis is more than a guess!A hypothesis is more than a guess! Often, Often,

it is based on what you already know.it is based on what you already know. See handout on Dwarf Wedge Mussels.See handout on Dwarf Wedge Mussels. To test their hypothesis, the students made a To test their hypothesis, the students made a

predictionprediction which is a logical statement about which is a logical statement about what will happen if the hypothesis is correct.what will happen if the hypothesis is correct.

The Scientific Method The Scientific Method (continued)(continued) ExperimentExperiment – a procedure designed to test a – a procedure designed to test a

hypothesis under controlled conditions.hypothesis under controlled conditions. Experiments must be designed to pinpoint cause-Experiments must be designed to pinpoint cause-

and-effect relationships. So, a single and-effect relationships. So, a single variablevariable is is tested and a tested and a controlcontrol is used. is used.

Scientists usually study two groups at a time:Scientists usually study two groups at a time: The group that receives the experimental The group that receives the experimental

treatment is called treatment is called the experimental group.the experimental group. The group that doesn’t receive the experimental The group that doesn’t receive the experimental

treatment is called treatment is called the control group.the control group. The The variablevariable is the single factor of interest is the single factor of interest

and it is the only difference between the and it is the only difference between the experimental group and the control group.experimental group and the control group.

The Scientific Method The Scientific Method (continued)(continued)

Collecting Collecting datadata – the information a – the information a scientist gathers during an scientist gathers during an experiment which is usually in experiment which is usually in numerical form.numerical form. Scientists organize their data into Scientists organize their data into

tables, charts, and/or graphs. This tables, charts, and/or graphs. This makes it easier for them to makes it easier for them to communicate their findings to others.communicate their findings to others.

The Scientific Method The Scientific Method (continued)(continued)

Reaching a Reaching a conclusionconclusion – – Scientists study their data to determine Scientists study their data to determine

the results from their experiment. the results from their experiment. Scientists compare the outcome of their Scientists compare the outcome of their

experiment to their prediction.experiment to their prediction. A conclusion is made.A conclusion is made. Often, experiments are repeated to see Often, experiments are repeated to see

if the results are reliable.if the results are reliable.

The Scientific Method:The Scientific Method:Observation

Question

Analyze Data

Conclusion

Scientific Habits of MindScientific Habits of Mind

Good scientists share some key Good scientists share some key “habits of “habits of mind”mind” or ways of approaching or thinking or ways of approaching or thinking about things:about things: CuriosityCuriosity – a genuine interest in a subject leads – a genuine interest in a subject leads

to wanting to learn more about it.to wanting to learn more about it. The Habit of SkepticismThe Habit of Skepticism – not believing – not believing

everything you are told.everything you are told. Openness to New IdeasOpenness to New Ideas – keeping an open – keeping an open

mind as to how the world works.mind as to how the world works. Intellectual HonestyIntellectual Honesty - being honest about your - being honest about your

resultsresults Imagination and CreativityImagination and Creativity – ability to – ability to

conceive new ideas, see patterns that others conceive new ideas, see patterns that others cannot, or to imagine things others cannot.cannot, or to imagine things others cannot.

What’s the difference What’s the difference between a hypothesis and a between a hypothesis and a prediction?prediction? A A hypothesishypothesis is a testable idea that is a testable idea that

leads to an experiment.leads to an experiment. A A predictionprediction is a logical statement is a logical statement

about what will happen if the about what will happen if the hypothesis is correct.hypothesis is correct. For example, the Keene High School For example, the Keene High School

students students hypothesizedhypothesized that phosphate that phosphate fertilizers from lawns were washing into fertilizers from lawns were washing into the river and killing the mussels.the river and killing the mussels.

The students may have The students may have predictedpredicted that that mussels will die when exposed to high mussels will die when exposed to high levels of phosphate in the water.levels of phosphate in the water.

Making CorrelationsMaking Correlations Scientists study questions by doing experiments. But Scientists study questions by doing experiments. But

what if an experiment can’t be done?what if an experiment can’t be done? Scientists can test predictions by examining Scientists can test predictions by examining

correlations – associations between two or more correlations – associations between two or more events.events.

The width of rings in a tree trunk indicate the amount The width of rings in a tree trunk indicate the amount of rainfall the tree received in a given year. Trees of rainfall the tree received in a given year. Trees produce wide rings in rainy years and narrow rings in produce wide rings in rainy years and narrow rings in dry years.dry years.

Scientists used this information to investigate why Scientists used this information to investigate why most of the first settlers at Jamestown, VA died.most of the first settlers at Jamestown, VA died.

The rings of very old trees on the Virginia coast The rings of very old trees on the Virginia coast indicate that the Jamestown colony was founded indicate that the Jamestown colony was founded during one of the worst droughts ever recorded. The during one of the worst droughts ever recorded. The settlers most likely died from starvation as a result of settlers most likely died from starvation as a result of not being able to farm.not being able to farm.

Rings of a Tree Trunk Rings of a Tree Trunk Can be Used to Make Can be Used to Make

Correlations:Correlations:

Students at Keene High School Students at Keene High School Study Dwarf Wedge MusselsStudy Dwarf Wedge Mussels

Read the “Case Study” Read the “Case Study” on page 35 and on page 35 and answer the answer the following following questions:questions:

1. Explain what students 1. Explain what students placed into each of the placed into each of the two tanks.two tanks.

2. What 4 things were to be 2. What 4 things were to be constant (identical) when constant (identical) when setting the tanks up?setting the tanks up?

3. What did the students do 3. What did the students do to the experimental to the experimental group?group?

4. What did they do to the 4. What did they do to the control group?control group?

5. What does replication 5. What does replication mean and how could the mean and how could the students replicate their students replicate their experiment?experiment?

1. The students have observed 1. The students have observed that____________.that____________.

2. The students also have 2. The students also have observed that the______ is observed that the______ is __________.__________.

3. These observations 3. These observations prompted the students to prompted the students to take the next step in the take the next step in the experimental method - experimental method - __________ a ____________.__________ a ____________.

4. What two trends did the 4. What two trends did the students notice?students notice?

5. When students tested the 5. When students tested the water, what did they find?water, what did they find?

6. What are phosphates?6. What are phosphates?7. How might phosphates end 7. How might phosphates end

up in the water?up in the water?8. What was the prediction the 8. What was the prediction the

students made?students made?9. What is the difference 9. What is the difference

between a hypothesis and a between a hypothesis and a prediction?prediction?

Review of Chapter 2, Review of Chapter 2, Section 1:Section 1:

1. Describe the steps of the experimental method.1. Describe the steps of the experimental method.2. Name 2. Name threethree scientific habits of mind scientific habits of mind andand

explain their importance.explain their importance.3. Explain why a hypothesis is not just a guess.3. Explain why a hypothesis is not just a guess.

Vocabulary WordsVocabulary Words::observationobservationhypothesishypothesispredictionpredictionexperimentexperimentvariablevariableexperimental groupexperimental groupcontrol groupcontrol groupdatadatacorrelationcorrelation

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

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 12 + 25 + 32 + 6 = 75 75/4 = 18.75

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.

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.

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.

Models

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

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).

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.

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.

Mathematical Models

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

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

2.3 – Making Informed 2.3 – Making Informed DecisionsDecisions

Scientific research is the first step to Scientific research is the first step to solving environmental problems.solving environmental problems.

Many factors must be considered before Many factors must be considered before decisions can be made about solutions:decisions can be made about solutions: How will people’s lives be affected?How will people’s lives be affected? How much will it cost?How much will it cost? Is the solution ethical?Is the solution ethical?

Questions like the ones above require Questions like the ones above require an examination of an examination of valuesvalues..

What are values?What are values? ValuesValues are moral principles we consider are moral principles we consider

important.important. Which values should influence decisions Which values should influence decisions

we make about our environment?we make about our environment? Economic – the gain or loss of money or jobsEconomic – the gain or loss of money or jobs Environmental – the protection of natural Environmental – the protection of natural

resourcesresources Ethical/moral – what is right or wrongEthical/moral – what is right or wrong Health – the maintenance of human wellbeingHealth – the maintenance of human wellbeing Social/cultural – maintaining human Social/cultural – maintaining human

communities, their values and traditionscommunities, their values and traditions

An Environmental An Environmental Decision-Making ModelDecision-Making Model

A A decision-making model decision-making model is a is a conceptual modelconceptual model that provides a that provides a systematic process for making systematic process for making decisions.decisions.

Gather Informatio

n

Consider Values

Explore Consequen

cesMake a Decision