Introduction to the PROCESS OF SCIENCE (aka the Scientific Method) Biology 11

The Scientific Method Science is based on LOGIC and uses the SCIENTIFIC METHOD to differentiate between CORRELATION and CAUSATION. **CORRELATION DOES NOT MEAN CAUSATION** Just because two things happen together, does not mean one is causing the other e.g. leave my umbrella at home and it rains e.g. eat a cookie and have a headache

Life before the Scientific Method.... A world of beliefs rather than science Examples: All matter is made up of fire, water, earth and air The world is flat Activity: MP and the Quest for the Holy Grail Video & Worksheet Some ideas still exist today as superstitions or pseudoscience Black cats are bad luck Three easy steps that will change your love life forever!

The Danger of Pseudoscience There are many examples of pseudoscience in magazines, on television, and on the internet ACTIVITY: Find an Example of Pseudoscience Online

The Danger of Pseudoscience

STEPS of the Scientific Method 1. OBSERVATION 2. QUESTION 3. PREDICTION/HYPOTHESIS 4. EXPERIMENTATION 5. CONCLUSION

STEPS of the Scientific Method 1. OBSERVATION -what do you see/smell/hear/taste/touch? One plate was accidently left open overnight and was contaminated with a fungus. It looked something like this… 1928 Alexander Fleming

STEPS of the Scientific Method 2. QUESTION What is going on??? A question must be TESTABLE and look at the RELATIONSHIP between two things (in this case, bacterial growth and the contaminated fungal region) e.g. Why is there no bacterial growth around the contaminated fungal region?

STEPS of the Scientific Method 3. PREDICTION/HYPOTHESIS A PREDICTION is an expected outcome A HYPOTHESIS is a testable statement that proposes a possible explanation for an observation. Formal hypotheses use an IF (statement or relationship is true) THEN (you would expect a certain result) format. e.g. If penicillin has antibacterial properties, then bacteria will not grow in or around the fungus

STEPS of the Scientific Method 4. EXPERIMENTATION This must be REPEATIBLE and have at least 30 REPLICATIONS (aka experimental units) to prove a relationship is significant

STEPS of the Scientific Method An experiment compares two groups: 1. Experimental Group- receives some kind of treatment e.g. fungal contamination 2. Control Group- receives no treatment e.g. no fungal contamination

STEPS of the Scientific Method Example of experimental units: Fungal Contamination No Fungal Contamination Treatment/Experimental Group X 30 Control Group X 30

STEPS of the Scientific Method Everything about the two groups except the treatment you are testing must remain exactly the same. This means same temperature, same amount of light, same moisture, etc. Why do you think this is?  to ensure the differences you see between the experimental treatment and control are caused by the treatment you applied and not some other variable.

STEPS of the Scientific Method The experiment looks at the relationship between two things, or variables. These are called the: 1. INDEPENDENT VARIABLE= the factor you change/add to the experiment, in this case fungal contamination (= x-axis) 2. DEPENDENT VARIABLE= what happens as a result of that treatment, what you are measuring, in this case, bacterial growth (= y-axis)   The dependent variable DEPENDS on the independent variable

STEPS of the Scientific Method There are two types of data collection: 1. QUALITATIVE data is NON-NUMERICAL Example: red, hot, happy, rough 2. QUANTITATIVE data is NUMERICAL Example: 10 cm, 101 seconds, 35°C Quantitative data is usually organized into a table and/or graph

STEPS of the Scientific Method Example of Independent and Dependent Variables using Quantitative Data: Bacterial Growth (Dependent Variable) Treatments (Independent Variable) #1= Treatment #2= Control

STEPS of the Scientific Method 5. CONCLUSION Scientists will examine the data to determine whether the hypothesis was rejected or accepted. Often, they use STATISTICS to see if the difference between treatments was real or just happened by random chance. Technically, a hypothesis can be supported but never “proven” true.

CONCLUSION Two possible outcomes: The results support/fail to reject the hypothesis (as far as we can tell, there is a significant relationship) or The results reject the hypothesis (there is no significant relationship)

THEORY What is a Theory? A theory is an explanation for natural events that is based on a LARGE NUMBER of observations. It is important to realize that theories EXPLAIN what we observe. Examples: Kinetic Molecular Theory, Big Bang Theory, Theory of Evolution

THEORY So to recap: theories must explain a wide range of observations theories must be falsifiable theories can be changed if new evidence presents itself. Example: the Germ Theory explains why we get sick and why we get infections. It uses observation of viruses and bacteria as well as data from those who get ill to create a theory on what causes the illness.

In Summary Worksheet on the Scientific Method Quiz