What is the the Scientific Method?

A stepwise, logical method used to answer questions- science related or not • Karl Pearson suggested “scientific habit of mind” to solve all problems

When is the scientific method used?

 Solve problems

 Answer questions

 Understand the world around us

Who uses the scientific method?

A. Only scientists

B. Science Students

C. Lawyers and Judges

D. Everyone

E. Nobody uses the scientific method. It is only taught in schools? Why do we even have to learn it??

Stephen Hillenburg – Marine Biologist and creator of Sponge Bob

What does a scientist look like?

Are these scientists?

What are the Steps of the scientific method?

• OBSERVATION

• QUESTION OR PURPOSE

• HYPOTHESIS

•  Controlled Experiment

• ANALYSIS

• CONCLUSION

OBSERVATION

•  Gathering information •  Using your own 5 senses and/or enhancing

those senses by using specific tools

Which of these are observations?

A.  This room is hot today

B. Everyone in this class is 15 years old.

C. The goggles are kept in the white cabinet.

D.  Every student in this school will go to lunch when the bell rings after the third hour of the day

What are the Steps of the scientific method?

• OBSERVATION

• QUESTION OR PURPOSE

• HYPOTHESIS

•  Controlled Experiment

• ANALYSIS

• CONCLUSION

Question/purpose

• Is salt bad for you?

• Does the earth revolve around the sun or does the sun revolve around the earth?

• Are there aliens in this universe?

• To determine if bacteria is found everywhere.

• Humans are at the top of the food chain.

• All living things made up of cells.

Hypothesis  An educated guess proposed to answer a

specific question

  Based on observations and predictions

 Offers a “testable” solution to a problem

  Should be used to answer one question at a time

 Contains the independent and dependent variable in the statement

 

Identify the following statements as either an observation, hypothesis, question or purpose.

A.  The grasshoppers will be able to live in a box containing leaves

B. Grasshoppers are always found wherever there are a lot of plants

C. What do grasshoppers eat?

D.  I want to find out what a grasshopper eats.

What are the Steps of the scientific method?

• OBSERVATION

• QUESTION OR PURPOSE

• HYPOTHESIS

•  Controlled Experiment

• ANALYSIS

• CONCLUSION

What is a Controlled Experiment?

 Used to test the hypothesis in a specific setting

 Can be in the laboratory or in the field(?)

 Has to be repeatable

 Always contains two groups or setups:

-control group where all the variables are constant and where the independent variable is missing

-experimental group where all variables are identical to the control and contains the independent variable

What is a variable?

A factor that is/could change during the course of the experiment. Ex: time, temperature, number of cells, number of bubbles Number of offspring, color/number of flowers/fruit/seeds/leaves etc.

Independent variable- factor that is being manipulated/changed by the experimenter. ex: time, temp, adding a fertilizer.

Dependent variable - factor that is changing or responding variable ex: number, color, height, weight etc

Control Variables

 Variables that are similar in both the control and experimental group. Ex.

 Hypothesis: To see the effect of plant growth with a fertilizer.

 What is your independent and dependent variable?

 Control variables: the type of plant, the amount of water, light, size of pot etc in both the experiment and control plants identical.

Which statement/s below are examples of a controlled

experiment?   Two grasshoppers in a cage and given

grass for food

  Two grasshoppers each in a different cage and given a similar type and amount of grass each day

  Two grasshoppers of similar size, each in a different cage- one given grass while the other given leaves for food.

You want to find out what type of food your cat likes. What will be the independent variable in your experiment?

A.  Your cat

B.  Type of food

C. When you feed your cat

D.  The amount of food you give your cat

E.   Weigh your cat every other day.

You want to find out what type of food your cat likes. What will be the control variable/s in your experiment?

A.  Your cat

B.  Type of food

C. When you feed your cat

D.  The amount of food you give your cat

E.   Weigh your cat every other day.

Data/Observations

Shows the results of the experiment. Should be organized – 2 types of data

1.  Quantitative data is arranged in tables charts, audio, video recordings

2.  Qualitative data is in the form of drawings, sketches, audio, video recordings

What are the Steps of the scientific method?

• OBSERVATION

• QUESTION OR PURPOSE

• HYPOTHESIS

•  Controlled Experiment

• ANALYSIS

• CONCLUSION

Analysis

Interpretation of the data and compare with the control to determine the validity of the experiment. i.e. experiment is compared to the control

Quantitative data uses mathematical and statistical tools to compare with the control Ex: mean, median, mode, percent, graphs, Qualitative data uses descriptive terms to compare with the control.

Conclusion Determine if the hypothesis was supported/or not.

Research similar works and provide a comparative in-depth analysis

Determine if the experiment was well designed. (Error Analysis)

Determine if the experiment needs to be repeated and/or modified- (Step Further)

Which of these represent quantitative data?

A

0

10

20

30

40

50

1/4/

98

1/5/

98

1/6/

98

1/7/

98

1/8/

98

Series 2

Series 1

B

Scientific Theory • A hypothesis that has been tested for its

predictive power many times and has not yet been found incorrect

• Has wide-ranging explanatory power – Atomic Theory – Darwin’s Theory of Evolution – Gravitational Theory –  String Theory

Which of the following is a scientific theory?

A.  Today is a good day

B. Most students in this school like pizza

C. The oxygen atom’s protons have a positive charge

D.  All protons have a positive charge

E.   My guess is more people live in NJ than CT.

Law – Explains an observation, usually with a mathematical equation. Ex: Mendel’s laws of Heredity, Newton’s Laws.

Scientific Law

Limits of Science

• Scientific approach cannot provide answers to subjective questions

• Cannot provide moral, aesthetic, or

philosophical standards

Science and the Supernatural

• Science has run up against religious

belief systems

– Copernicus suggested that sun, not the

Earth, was center of universe

– Darwin suggested that life was shaped by

evolution, not a single creation event

Asking Questions

• Scientists still ask questions that challenge widely held beliefs

• The external world, not internal conviction, is the testing ground for scientific beliefs

CONTROL GROUP Gets regular potato chips

EXPERIMENTAL GROUP Gets Olestra potato chips

Make Prediction

Eat potato chips Eat potato chips

Analyze Results

Draw Conclusion Eating Olestra potato chips

does not cause intestinal distress

If Olestra® potato chips cause intestinal distress then people who eat them will get cramps

Perform Experiment

93 of 529 people (17.6%) suffer from cramps later

89 of 563 people (15.8%) suffer from cramps later

About the same number of people in each group get cramps