THE SCIENTIFIC METHOD

L. BAKER8/04

Amended 1/07 S. Bray

• Science is ultimately based on observation

• Observation – perceiving objects or events using one of the five senses

Scientific Process

• Observations• Questions• Hypothesis (testable statement)• Experiment (planned procedure to

collect information to test the hypothesis)

• Analysis of Data• Conclusions

PART A

•What are the steps in the Scientific Method?

The STEPS are…1.State the

problem or question… Ask why.

What do you want to find out?

2. Gather background information… Research, learn

3. Form a hypothesis… a testable, possible explanation. What do you think will happen? If…then…

4. Test hypothesis… experiment, observe, make a model. Make a specific list of what will be done.

5. Analyze data – make tables, graphs, etc. What happened? What did you see, hear smell? [observations]

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3rd

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East

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North

6. Draw conclusion –what do the results mean? Was your hypothesis supported?

A hypothesis can never be Proved correct

• Nothing is ever proved in science, only supported or refuted!!!

• Ex. For hundreds of years, scientists believed that the earth was the center of the universe and the sun and stars revolved around the earth.

• Now we believe what? Will that ever change? Is Pluto a planet???

• Science is subject to change when new evidence is discovered.

Part B:Terms to Know• Independent

variable – determined and manipulated [what you change] in the experiment

• Dependent variable – changes in response to the independent variable [what happens]

• Constant – a variable that does not change when other variables change

• Control – a standard (conditions are kept the same) that can be used for comparison

More Terms

• Experimental Group – receives some kind of treatment or condition

• Control Group – Receives no treatment, used to compare

• *Everything about the two groups except the factor you are testing must remain exactly the same.

• Why???

THEORY vs. LAW

• Scientific theory – explanation based on knowledge gained.

• Scientific law – statement about what happens in nature that always seems to be true

Theories

• A theory explains what we observe• Ex. Germ theory explains why we

get sick with infections1. Theories must explain a wide range

of observations2. Theories must be falsifiable3. Theories can be changed if new

evidence presents itself

Scientific Law

Ex. Law of Gravity, 4 Laws of Thermodynamics, Newton’s 3 Laws of motion, Boyle’s Law of gases, Conservation Laws

Simple, universally true (have not yet been refuted)

Hypothesis

• Testable statement which can be supported or falsified by experiment or observation.

• There are good ways to state a hypothesis and bad ways

• Hypotheses must be stated in measurable terms.

• Bad1. Plants will grow better when

given Miracle Grow.

• Good1. Plants will grow taller when given

Miracle Grow.

• Bad2. Girls are smarter than boys.

• Good2. Girls will score higher on math

tests than boys.

• Bad3. Hermit crabs like colorful shells.

• Good3. Hermit crabs choose colorful

shells over drab shells.

Hypotheses must be Testable!

• You can’t test happiness or fear, love, likes or dislikes.

• Only things you can measure by experiment.

Collecting Data

• Scientists must carefully collect and organize data from the experiment

• Data should always be presented in a neat fashion

• Usually tables or graphs are used to show data so that trends can easily be observed

Tables are good for organizing and showing data

Graphs are better at showing trends in the data

Problem Solving in Physics

• Read the problem Carefully• Sketch the system• Visualize the physical process

(Einstein called it “thought experiments”)

• Strategize• Identify appropriate equations• Solve the equations

• Check your answer (Does the number make sense? Are the units right?)

• Explore limits/special cases (Does this make sense if x = 0)

ASSIGNMENT… ON ASSIGNMENT… ON CONSTRUCTION OR COLORED CONSTRUCTION OR COLORED PAPER, MAKE A FLOW CHART PAPER, MAKE A FLOW CHART

SHOWING THE SCIENTIFIC SHOWING THE SCIENTIFIC METHOD STEPSMETHOD STEPS

THE END

ETC.