Scientific Method

Biotechnology II

Scientific Method

• Process by which scientists have collectively agreed to conduct research– Tries to remove personal bias and

prejudice

• The conclusion should hold up irrespective of state of mind, religious persuasion, or personal bias

Scientific Inquiry

1. Purpose: why the experiment is being done or what have you observed

2. Research3. Hypothesis: your educated guess

about what the outcome will be4. Experiment: design with variables5. Analysis6. Conclusion

Flow Diagram

Testing your Hypothesis

• Testing is done to prove or disprove the hypothesis

• Experiments may test the theory directly or they may test for consequences derived from the theory using math and logic– Example: rate of radioactive decay– They can observational or experimental

• All theories must be able to be tested or they do not qualify as scientific theories

Errors in Experiments

• Random Errors: errors which have equal probability of producing a higher or lower result– Instrument error is an example

• Non Random Errors: systematic error which causes a bias in one direction in the results– Operator error such as not using a blank in a

spectrophotometer will skew all of your data in one direction

• Sources of Error go in your Results section of your research paper.

Procedure for Scientific Experiment

• Plan– Write a step by step plan of what you will do– Start with your research question, hypothesis

and material list– Visualize yourself doing it while you write

• Research Question: write it using independent and dependent variables.– What effect does (independent) have on

(dependent)

Procedure for Scientific Experiment

• Hypothesis– Guess what you think the result will be.

WRITE it down. Explain why.

• Materials: describe in detail all the materials required including quantities

Procedure for Scientific Experiment

• Detailed Experimental Plan– Setup of materials and equipment– Independent variable – explain exactly what you will

change and how you will change it– Constant – explain exactly how you kept all other

variables constant– Controls – what standard or control will you use to

determine if changes have occurred. Control groups are untreated if this is a drug experiment.

– Dependent variable – explain exactly what will probably change because you changed the independent variable

– Trials – explain how many times you will conduct this experiment

Procedure for Scientific Experiment

• Detailed Experimental Plan– Data Chart – create a chart to record results.

You need at least 3 trials for each change of the independent variable.

– Do the Experiment – EXACTLY as planned. You MUST record any changes and REWRITE your plan so others can follow what you did EXACTLY

– Repeated Trials – repeat your work to verify results

– Log – record everything in your lab notebook– Pictures – draw pictures or take pictures where

possible

Procedure for Scientific Experiment

• Conclusion– Results with Explanation and

Evidence Summary – summarize your data; do you accept or reject your hypothesis and why?

– Possible Errors – what could have affected your results?

– Practical Applications – how can your conclusion apply to the real world?

Writing a Scientific Paper

• Sections in a scientific paper– Introduction– Materials and Methods– Results– Discussions– Literature cited

Scientific Method Lab

• Sunshine.chpc.utah.edu/labs/scientificmethod/sci_method_main.html– This is an online interactive lab which is

a good overview and would be worthwhile reviewing as a class after the basic lecture material.

• www.brightminds.uq.edu.au/thelab/scientific_method.html– Fermentation lab could be done