Scientific MethodKaren J. Dalton

Community College of Baltimore CountyCatonsville Campus

• Observations– What you know before you begin an experiment

• Accepted scientific knowledge– Journals, textbooks

• What you see in the world around you

– What did Semmelweis observe?

• What is the problem? Ask a question?– What did he ask?

• Hypothesis: Educated answer to your question– Must be based on accepted science– What is your answer to Semmelweis’ problem?

• Test you hypothesis– Experimental design

• Control groups vs. experimental groups• Large numbers in the groups• Repeatable experiments

– How did Semmelweis test his hypothesis?

• Results– Data collected as a result of the experiment

• Conclusions– What do your results mean?– Results are new observations

• Should you now alter your hypothesis?

• Theory–Well substantiated explanation of

something in the natural world• Explanation uses many different pieces of

evidence• Examples: cell, atomic, evolution,

chromosomal inheritance

– In science this is “as good as it gets”– Lay people use the word theory when

they should be using the word hypothesis