Scientific Method

Steps in the Scientific Method Observation Observation Identify the Problem Identify the Problem Hypothesis Hypothesis Gather information Gather information Experiment Experiment Organize Data Organize Data Conclusion Conclusion Communication Communication

1. Observations Gathered through your senses Gathered through your senses A scientist notices something in their natural world A scientist notices something in their natural world

Observations An example of an observation might be noticing that many salamanders near a pond have curved, not straight, tails An example of an observation might be noticing that many salamanders near a pond have curved, not straight, tails

2. Identify a Problem Ask a question about the observation you made. Ask a question about the observation you made. State it clearly and as a question State it clearly and as a question

Identify the Problem Example: Why do salamanders living near a pond have curved tails? Example: Why do salamanders living near a pond have curved tails?

3. Hypothesis A suggested solution to the problem. A suggested solution to the problem. State what you think will happen State what you think will happen Must be testable Must be testable Predicts an outcome Predicts an outcome

Hypothesis An example of a hypothesis might be that the salamanders have curved tails due to a pollutant in the moist soil where they live. An example of a hypothesis might be that the salamanders have curved tails due to a pollutant in the moist soil where they live.

4. Gather information Research your topic Research your topic Discover what is already known about the topic Discover what is already known about the topic

5. Experiment A procedure to test the hypothesis. A procedure to test the hypothesis.

Experiment  Variable – factor in the experiment that is being tested

Experiment A good or “valid” experiment will only have ONE variable! A good or “valid” experiment will only have ONE variable!

Scientific Experiments Follow Rules An experimenter changes one factor and observes or measures what happens.

Variables The factor that is changed is known as the independent variable. The factor that is changed is known as the independent variable. The factor that is measured or observed is called the dependent variable. The factor that is measured or observed is called the dependent variable.

Variables Independent Variable – Pollution is added to an area near a population of salamanders with straight tails Independent Variable – Pollution is added to an area near a population of salamanders with straight tails Dependent Variable – the tails of the salamanders are observed Dependent Variable – the tails of the salamanders are observed

The Control Variable The experimenter makes a special effort to keep other factors constant so that they will not effect the outcome. The experimenter makes a special effort to keep other factors constant so that they will not effect the outcome. Those factors are called control variables. Those factors are called control variables.

What is the Purpose of a Control? Controls are NOT being tested Controls are NOT being tested Controls are used for COMPARISON Controls are used for COMPARISON Compare the control group with the experimental group (the one you are testing) Compare the control group with the experimental group (the one you are testing)

What is the Purpose of a Control? Control Group – salamanders with straight tails living normally Control Group – salamanders with straight tails living normally Experimental Group – salamanders with straight tails and added pollution in the soil Experimental Group – salamanders with straight tails and added pollution in the soil

Another Example For example, suppose you want to figure out the fastest route to walk home from school. You will try several different routes and time how long it takes you to get home by each one. Since you are only interested in finding a route that is fastest for you, you will do the walking yourself.

Another Example Varying the route is the independent variable Varying the route is the independent variable The time it takes is the dependent variable The time it takes is the dependent variable Keeping the same walker throughout makes the walker a control variable. Keeping the same walker throughout makes the walker a control variable.

One more thing… it is best to make several trials with each independent variable.

Remember! To be a Valid Experiment: Two groups are required --- the control & experimental groups There should be only one variable you are testing

6. Organize Data Results of the experiment Results of the experiment May be quantitative (numbers) or qualitative (observations) May be quantitative (numbers) or qualitative (observations)

Organize Data Must be organized to find out what it means Must be organized to find out what it means Can be organized into charts, tables, or graphs Can be organized into charts, tables, or graphs

7. Conclusion Explain the data that you collected from the experiment Does it support your hypothesis? Should anything else be done?

8. Communicate the results Don’t be greedy! Don’t be greedy! Let others know what you learned so that progress can be made Let others know what you learned so that progress can be made

Scientific Method 1) Make observations 2) Identify a Problem 3) Form a Hypothesis about the problem 4) Research and gather information 5) Design an Experiment to test the hypothesis 6) Organize Data 7) Form a Conclusion 8) Communicate the results

Quiz! In your notebooks reflect on the following: In your notebooks reflect on the following: What are the 8 steps to the scientific method: What are the 8 steps to the scientific method: What is the scientific method used for? What is the scientific method used for?