What is Science? -A process that produces a body of knowledge about nature. -Science is concerned with the collection of facts, and especially the interpretation and analysis of those facts.

Science uses the Scientific Method to answer questions about nature. -The Scientific Method follows very specific steps, and uses a Controlled Experiment to come to a valid conclusion.

A Controlled Experiment is one where only one factor is changed at a time. Control Group: the group not being tested, serves as a comparison Experimental Group: the group being tested (variable group)

Scientific Method 1)Observation/Fundamental Question 2) Interpretation/Background Research 3)Hypothesis 4)Experiment/Data Analysis 5)Conclusion

Alexander Fleming ( ) -discovered penicillin (antibiotic) by accident. -used the Scientific Method to check his discovery, and to make sure any ideas were valid.

Fleming was a bacteriologist, meaning he studied bacteria. Fleming was working with a bacteria called Staphylococcus. Staphylococcus has been shown to cause a great number of diseases in man.

-Fleming found mold growing on a Petri dish of bacteria, and saw that the bacteria died around the area where the mold was growing. Observation! Did the mold cause the bacteria to die off?

Bacterial Cultures with “dead zones” around mold colonies

Fleming then did some checking to see what kind of mold it was growing on his dish. Background Research! “If I did an experiment, what would I use?”

Penicillium notatum on an orange Fruiting bodies of the penicillium mold

Fleming then guessed that the mold was in some way killing the bacteria. Hypothesis! “If I put some penicillium on the bacteria, then they will die”.

Fleming proceeded to put the mold on bacterial cultures, and looked to see if the bacteria were killed. Experimentation! He kept some bacterial cultures “clean” so he had a comparison

Fleming did not just try the experiment on one petri dish and call it a success. He replicated both the CONTROL and the EXPERIMENTAL many times. Replication is key to minimizing variation.

Fleming also treated both the CONTROL and the EXPERIMENTAL in exactly the same manner. All variation EXCEPT that caused by the desired variable needs to be eliminated, or at least minimized. Otherwise, what REALLY caused the difference?

Which dish is the experimental, and which is the control? Why? AB C

Fleming was able to prove that it was only the Penicillium mold that caused the bacterial cultures to die. Conclusion! “Based on my experiments, I can conclude that the Penicillium mold causes the bacteria to die.”

Kinds of Data: Qualitative: expresses a quality about the observation EX: Color, texture, smell Quantitative: Implies some kind of number or measurement EX: weight, height, temperature