Presentation on theme: "Scientific Method A Review for Zoology Class. Have a problem to solve??? Anytime we have a question that needs to be answered or a problem that needs."— Presentation transcript:
Scientific Method A Review for Zoology Class
Have a problem to solve??? Anytime we have a question that needs to be answered or a problem that needs to be solved we go through a process known as the “scientific method” to help us solve that problem. Every problem is not solved in the same way. These steps represent a “typical” scientific process.
Steps in the Scientific Method Question/Problem Question/Problem Observations Observations Hypothesis Hypothesis Experiment Experiment Data Collection Data Collection Conclusion Conclusion Retest Retest
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
Hypothesis A suggested solution to the problem (an educated guess) A suggested solution to the problem (an educated guess) Must be testable Must be testable Sometimes written as If…Then… statements Sometimes written as If…Then… statements 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.
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 true variable!
Controls and Variables What do you already know?
Scientific Experiments Follow Rules An experimenter changes one factor and observes or measures what happens.
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? Remember the Controls are factors NOT being tested - Controls or control groups are used for COMPARISON.
Other Variables The factor that is changed is known as the independent variable. The factor that is measured or observed is called the dependent variable.
Example of Controls & Variables 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.
What are the Variables in Your Experiment? 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.
Valid Experiments What do you remember?
Remember: To be a Valid Experiment: Two groups are required --- the control & experimental groups. There should be only one true variable – one factor you are changing.
Data Results of the experiment. May be quantitative (numbers) or qualitative (descriptive words).
Data Must be organized. Can be organized into charts, tables, or graphs.
Conclusion The answer to the hypothesis based on the data obtained from the experiment.
Retest In order to verify the results, experiments must be retested. Good experiments are valid and reliable.
Solving a Problem 1)Identify a Problem 2) State Observations about the problem 3) Form a Hypothesis about the problem (if…then…) 4) Design an Experiment to test the hypothesis 5) Collect Data 6) Form a Conclusion 7) Retest
Accuracy Vs. Precision Accuracy – getting the right answer or “hitting the bulls eye” Precision – the ability to be accurate over and over, consistency in answers/skill
Theory Versus Law Scientific Theory - A logical explanation of observed events. Example – Theory of evolution. Scientific Law - A theory that has been tested and widely accepted as true. Example – Law of thermodynamics.