Beaver Lake Middle School

Eighth Grade Science

The Scientific Method: Fleming                 Name:_________________

                                                                                    Date: ______Period: _____

 

In 1928, Sir Alexander Fleming was studying Staphylococcus bacteria grown in culture dishes. He noticed a mold called Penicillium also growing in some of the dishes. A clear zone existed around the mold. All the bacteria that had grown in this clear zone had died. In the culture dishes without mold, no clear areas were present.  The bacteria lived in these dishes.

Fleming inferred or reasoned that the mold must be producing a chemical that killed the bacteria. He decided to isolate this mold and then test the mold to see if it would kill bacteria. Fleming transferred the mold to a nutrient broth solution. This solution contained the materials the mold needed to grow and reproduce. He allowed the mold to grow, and then he removed the mold from the nutrient broth. Fleming added the nutrient broth in which the mold had grown to the bacteria. He observed that the bacteria were killed. Fleming added nutrient broth that had no mold growing in it to another dish of bacteria. The bacteria in this dish were not killed.

Fleming concluded that the mold produced a bacteria-killing substance in the broth. He called the substance that killed the bacterial “penicillin”.

 

Answer all of the following in COMPLETE SENTENCES on this paper:

 

  1. Identify the problem Fleming wanted to solve by writing an Investigative (operational) Question. Include correct format with an MV and RV.

 

 

 

 

 

  1. What was Fleming’s hypothesis? Write correct format (be sure to include a reason).

 

 

 

 

 

 

  1. How did Fleming test his hypothesis? Briefly describe his experiment.

 

 

 

 

 

  1. List the following variables in Fleming’s experiment?

·         Manipulated Variable (MV)

 

 

·         Responding Variable (RV)

 

 

  1. List 5 Controlled Variables (CV) Fleming might have kept constant during his experiment.

 

 

 

 

 

  1. What DATA did Fleming collect for his experiment?

 

 

 

 

 

  1. What was Fleming’s conclusion? Give brief statement of his major finding.

 

 

 

 

 

 

  1. Did his data support his hypothesis?  Explain.

 

 

 

 

 

 

 

  1. What was discovered as a result of Fleming’s experiments?

 

 

 

 

  1. What is a theory? – Define Theory

 

 

 

 

 

  1. How do you think hypotheses, observation, and conclusions relate to theories?