The Scientific Method

The Scientific Method An organized way to solve a problem through experimentation & observation.

The 6 Steps of the Scientific Method

Example: Mouthwash kills bacteria. Which brand works best? 1. State the Problem Form a question about a specific event Example: Mouthwash kills bacteria. Which brand works best?

2. Collect Information Research the problem Example: Read the labels of types of mouthwash Which has the most antiseptic (germ-killing) ingredients.

3. Form a hypothesis Make a testable educated prediction based on your research. A hypothesis can be recognized by an “if, then” statement. Example: IF Listerine has more antiseptic ingredients than Crest or the Wal-Mart brand, THEN it will kill more bacteria.

4. Design an Experiment Create a way to test your hypothesis. Create a CONTROLLED experiment.

A controlled experiment MUST have 2 groups. CONTROL GROUP: all conditions remain the SAME! It is a group you do not do anything to. EXPERIMENTAL GROUP: a group or many groups who you test. The experiment is performed on this group.

Establish the variables for your experiment. INDEPENDENT VARIABLE: the variable that you change or manipulate (X axis for graphing) DEPENDENT VARIABLE: the change or result that happens when the independent variable is used (Y axis for graphing)

Mouthwash Experiment Control Group -no mouthwash Experimental Group Petri dish Bacteria grown from swab Listerine Experimental Group Crest Brand Wal-Mart brand

Type of Mouthwash Mouthwash Experiment Amount of bacteria killed INDEPENDENT VARIABLE: Type of Mouthwash DEPENDENT VARIABLE: Amount of bacteria killed

Run the experiment & document the data 5. Collect & Analyze Data Run the experiment & document the data

2 Types of Data QUANTITATIVE: numerical data, deals with specific quantities, usually in the form of a graph or chart QUALITATIVE: descriptive data, describes how something looks, smells, sounds, or feels; deals with qualities

QUANITATIVE EX: Area of Inhibition for Mouthwash Brands QUALITATIVE EX: The control group and the Wal-Mart brand have a strong smell; the Listerine & Scope don’t smell as bad. QUANITATIVE EX: Area of Inhibition for Mouthwash Brands Control Listerine Scope Wal-Mart 5 min 0 mm 3 mm 2 mm 1 mm 10 min 4 mm 15 min 6 mm 5 mm 20 min 8 mm

6. Draw Conclusions Determine from the data collected if the hypothesis was correct or incorrect EX: Listerine did kill more bacteria than the other brands because it had more antiseptic ingredients.

Scientific Method Vocabulary Observation- the act of observing (touch, taste, smell, feel, see, etc.) Inference- a quick conclusion that attempts to explain an observation Prediction- to forecast; to guess the outcome of a situation beforehand Analysis- to separate or break apart into smaller sections for study

Scientific Method Vocabulary Conclusion- to close or bring to an end; to accept or reject a hypothesis in an experiment Data- recorded observations or measurements Hypothesis- a tentative explanation that accounts for a set of facts & that can be tested by further investigation

Scientific Method Vocabulary Controlled Experiment- an experiment in which all variables except the ONE being tested are identical in order to make the experiment fair & the results reliable Variable- any factor in an experiment that could affect the results & is therefore tested separately

Scientific Method Vocabulary Controlled Variable- a variable that is not changed Independent Variable – a variable that you purposely manipulate (manipulated variable) Dependent Variable- the variable being observed that changes in response to the independent variable (responding variable)

Scientific Method Vocabulary Quantitative Data- data that involves numbers or measurement usually in the form of a chart or graph Qualitative Data- anecdotal or descriptive data that does NOT involve numbers or measurement