The Scientific Method The Scientific Method An organized

The Scientific Method

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

The 6 Steps of the Scientific Method

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

2. Collect Information • Research the problem EX: Read the labels of 3 common brands of mouthwash and see which has the most antiseptic (germ-killing) ingredients.

3. Form a hypothesis • Make an educated guess based on your research. A hypothesis can be recognized by an “if, then” statement. EX: If Listerine has more antiseptic ingredients than Scope or Wal-Mart brand, then it will kill more bacteria.

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

• A controlled experiment MUST have 2 groups. CONTROL GROUP: all conditions remain the same EXPERIMENTAL GROUP: only the condition that you are testing for is changed ONLY 1 condition is changed!

• Establish the variables for your experiment. INDEPENDENT VARIABLE: the variable that is changed, manipulated (X axis for graphing) DEPENDENT VARIABLE: the change caused by the manipulation of the independent variable (Y axis for graphing)

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

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

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

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 5 min 10 min 15 min 20 min Control Listerine Scope Wal-Mart 0 mm 3 mm 4 mm 6 mm 8 mm 1 mm 3 mm 4 mm 2 mm 3 mm 5 mm 6 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.

Progression of Ideas in Science • Hypothesis- a possible explanation to a question based on information the scientist has already gathered - If experiments show a hypothesis to be correct, other scientists may accept it as support for a scientific theory. EX: Plants obtain their energy from the sun.

Progression of Ideas in Science • Scientific Theory- a general statement of why things work based on hypotheses that have been tested many times

Progression of Ideas in Science - Theories are used to explain & predict the outcome of other experiments - Theories must be tested - Sometimes they are wrong & must be modified or discarded EX: The Earth is flat.

Progression of Ideas in Science • Scientific Law- a statement of what happens in a certain event based on verified observations & experiments

Progression of Ideas in Science - Explains what happens & not why - Summaries of the results of many, many experiments & observations - When results of a series of experiments are the same each time they no longer need to be tested EX: Newton’s Law of Gravity

Progression of Ideas in Science • Which one is most likely to be wrong- hypothesis, theory, or law? 1. 2. 3. Hypothesis Theory Law

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 • Theory- an explanation of a large body of information, experimental and inferential, and serves as an overarching framework for numerous concepts. It is subject to change as new evidence becomes available. • Law- a basic scientific theory that is no longer tested & is generally accepted as true (Newton’s Law of Gravity)

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

BIO SOL: 1 a-m The student will plan and conduct investigations in which: • observations of living organisms are recorded in the lab and in the field; • hypotheses are formulated based on direct observations and information from scientific literature; • variables are defined and investigations are designed to test hypotheses; • graphing and arithmetic calculations are used as tools in data analysis; • conclusions are formed based on recorded quantitative and qualitative data; • sources of error inherent in experimental design are identified and discussed;

BIO SOL: 1 a-m The student will plan and conduct investigations in which: • validity of data is determined; • chemicals and equipment are used in a safe manner; • appropriate technology including computers, graphing calculators, and probeware, is used for gathering and analyzing data and communicating results; • research utilizes scientific literature; • differentiation is made between a scientific hypothesis and theory; • alternative scientific explanations and models are recognized analyzed; and • a scientific viewpoint is constructed and defended (the nature of science).