THE SCIENTIFIC METHOD Murtaugh 1A Living Environment

ESSENTIAL QUESTIONS  Why is it important to follow the steps of the scientific method?  What is the purpose of a control in an experiment?  What is the difference between a theory and a law?

VOCABULARY  Bias: making your experiment to turn out the way you want it to by changing the variables or measurements so it matches your hypothesis or changing your hypothesis after your experiment is completed.  Control: the portion or sample within the experiment that contains all components of the experiment EXCEPT the measured (dependent) variable.  Dependent Variable: is the way you are going to measure how the independent variable affects the experiment. This is the data being collected and recorded, it is known as the measured variable.  Hypothesis: is a possible answer or explanation to the problem (question), based on observations, known facts and scientific laws; usually stated in an “if….then….” format.  Independent Variable: is something in the experiment that is going to be changed (experimenter controls). Because of this it is also known as the manipulated variable.  Validity: means that is true with evidence and can be reliable/consistent

WHAT IS THE SCIENTIFIC METHOD?  The Scientific Method is a series of steps used not only by scientists but by everyday people to solve any kind of problem at hand.

WHAT ARE THE STEPS OF THE SCIENTIFIC METHOD? 1) Define the PROBLEM (the question) 2) Formulate a HYPOTHESIS 3) State your VARIABLES (design your experiment): * Control, dependent and independent 4) Carry out your EXPERIMENT 5) Collect, record, and analyze DATA 6) Form a CONCLUSION

DEFINE THE PROBLEM  The problem is not really a problem. It is what the scientists, or everyday person, is trying to find an answer to. An example of this would be, “Do plants need light to grow?”  It is always stated in the form of a question.

FORMULATE A HYPOTHESIS  A hypothesis is a possible answer or explanation to the problem (question). This is based on observations (quantitative and qualitative), known facts and scientific laws.  It is usually stated in an “if….then….” format.  Ex. If I deprive the plant of light, then it will not grow.

WHEN DESIGNING AN EXPERIMENT:  In order to prove or disprove the hypothesis, an experiment is designed. Scientists always carry out experiments in duplicate, or double, where all factors in each set up are identical, except for one, which is what is being tested.  This is called a controlled experiment.  The control in experiment is the portion or sample within the experiment that contains all components of the experiment EXCEPT the measured (dependent) variable.

STATE YOUR VARIABLES (DESIGN YOUR EXPERIMENTS)  In it’s simplest form, the independent variable is something in the experiment that is going to be changed (experimenter controls). Because of this it is also known as the manipulated variable.  The dependent variable is the way you are going to measure how the independent variable affects the experiment. This is the data being collected and recorded, it is known as the measured variable.

CARRY OUT YOUR EXPERIMENT  Set up a procedure ( a set of steps to follow, in order so someone else can replicate your experiment) with a list of materials. Follow it.  This is where you get to have some fun! You conduct the experiment in order to formulate an answer to your question; to prove your disprove your hypothesis.

COLLECT, RECORD, ANALYZE DATA The information, often in the form of some kind of measurement, and the observations made throughout the experiment are called data. The data is recorded in a data table. To further understand this data, it is then plotted in a graph. Analyze means to make sense out of the data.

CONCLUSION  Now that you have conducted your experiment, observe the results, collect the data, and form a conclusion.  Your conclusion should always include your hypothesis AND if your data supported it or rejected it.  Your HYPOTHESIS is NEVER WRONG or PROVEN CORRECT!  There may always be alternative hypothesis that might account for the results and that were not tested.  Even if your hypothesis is not supported, is your experiment a waste of time?  NEVER- you have always learned something from the data you have collected like your hypothesis is not supports and then you can design a new one.

ACCOUNTABILITY  Any good experiment should be repeatable with the same results being obtained. This proves the validity of the data and conclusions of the experiment.  Validity or being valid: means that is true with evidence and can be reliable/consistent  It is extremely important to keep bias out of your experiments.

LAW VS THEORY  A law is a statement based on repeated experimental observations that describes some aspects of the universe.  A scientific law ALWAYS applies under the same conditions, and implies that there is a causal relationship involving its elements.  There are not may scientific laws  A theory is an explanation based on observation, experimentation, and reasoning, especially one that has been tested and confirmed as a general principle helping to explain and predict natural phenomena.  Any scientific theory must be based on a careful and rational examination of the facts.  There are many scientific theories.

HAPPY PROBLEM SOLVING!!