Introduction to Scientific Method: Observation and Inference


Calvin and Hobbs: Complete column 1 and then read the back of the paper* before completing column 2.

1.  List 5 statements about the cartoon below 2.  Now, categorize the statements on the left as qualitative, quantitative, inference or opinion.





(Note the information required for the 2nd column is located further down this web page).















*Read the following information about observations and inferences before completing the second column in the table.


Observations are made when an organism uses their senses to understand the world around them. Observations can be recorded in two ways: qualitatively or quantitatively. Quantitatively refers to numbers or measurements; hence, the term quantity. Example: The movie starts at 8p.m. Or, it took one hour to walk the Golden Gate Bridge.  Qualitative are those observations made without numbers or measurements. Example: I heard the hawks screeching in the distant mountains. Or, something is tickling my skin.


Inferences are explaining observations. It is not just a guess but an explanation based on background information and experience. Example: I think the firewood is dry because it is crackling. The qualitative observation is hearing the wood crackling; whereas, the inference that the wood is dry is based on previous knowledge and experience that dry wood crackles and pops when it burns (not to be confused with Rice Crispies that crackle and pop when they are wet!). Another example: It must be around 3 p.m. because the fog is starting to roll in. The inference that it’s around 3 p.m. is based on observations made in the past that when the fog starts to roll in is in the mid afternoon. Notice that a statement with an inference usually has the word “because” in it because that word is used to explain something. (So, for that previous statement, can you pick out the observation and the inference? By now you should be able to!) Usually an inference answers “why” or “how” questions. Examples: Why did this happen? How did this happen? Why didn’t this work? Why is this here?