1:2 The Scientific Method

Step 1: State the Problem  Based on observations (gathering information using your senses)  Written in the form of a question:  What is the effect of Independent Variable on Dependent Variable?  Variables-characteristics in an experiment that change or could be changed  Independent variable- variable you change on purpose; also called the manipulated variable  Dependent variable- variable that responds to a change in the independent variable

Step 2: Research  Do research to find out:  Facts about the independent variable  Facts about dependent variable  Relationship between independent variable and dependent variable (If you can not establish a relationship, then you do not have enough information to make an educated guess that will lead to an experiment!)

Step 3: Form a Hypothesis  This is an educated guess about how changing the independent variable will effect the dependent variable  It is a possible explanation to the problem that is based on your research findings  Often written as an If…, then… statement to make sure that all necessary information is included

Step 4: Perform the Experiment  Keep ALL factors the same except the variables being tested  Constants-characteristics in an experiment that are kept unchanged in all trials  Control group- part of the experiment without the variable being tested; standard for comparison in an experiment  Experimental group- part of the experiment that contains the factor being tested  Change the independent variable in a regular, measurable fashion.  Measure changes in the dependent variable  Carry out at least 3 trials for each change of the independent variable  Trial- the number of times an experiment is repeated for each level or value of the independent variable. The more trials…the more reliable your results

Step 5: Record and Analyze Data  Quantitative data- can be described or measured in numbers  Qualitative data- using your senses to record written descriptions  Written description of all sensory data are recorded in a log or journal  Numerical measurements are recorded in a data table and are also displayed visually in the appropriate graph or chart, depending on the type of data involved  Data is analyzed by looking for patterns or relationships

Step 6: Draw Conclusions  Tells if the hypothesis was correct  Identifies scientific error  Explains why the results turned out that way…relate it to the research findings

Step 7: Report your results

Scientific Theories & Laws  Theory- A unifying explanation for a broad range of hypotheses and observations that have been supported by testing (tells you why)  Repeated testing that does not disprove a hypothesis  Law-a summary of many experimental results and observations (tells you what)  Considered a fact