Observation vs. Inference “You can observe a lot just by watching.” - Yogi Berra

What is an observation?  When you observe, you become aware of something using your senses.   Your five senses are smell, taste, sight, touch, and hearing.  In an observation you simply describe something you observe.   An observation is a statement of fact gathered by using your five senses.

Two Types of Observation QUALITATIVE   Qualitative observations describe what we observe using adjectives.  “Qualitative” = quality (descriptive)  Example: The flower has white petals.  Example: The music is loud.

Two Types of Observations  QUANTITATIVE   Quantitative observations measure what we observe using numbers.  “Quantitative” = quantity (numerical)  Example: The flower has seven petals.  Example: The volume was on 10 (max.).

Which is better?  Qualitative descriptions tend to be more subjective (dependant on the observer), while quantitative are more objective (independent of the observer).   Scientists make quantitative observations, which can be compared precisely and objectively.  Qualitative: The road is long. (describes)  Quantitative: The road is 7 km long. (measures)

Extending our Observations  Sometimes scientists must make very careful observations. There are some things that cannot be observed using just your senses. (Examples: radiation, sound waves, planets, cells, etc.)   Scientists use tools such as microscopes, telescopes, satellites to extend their senses.

What is an inference?   An inference is an explanation for an observation you have made.  They require thought and are based on your past experiences and prior knowledge.  They are often changed when new observations are made.  Again, observations are information we gather directly through our senses……Inferences help explain those observations.

Here are some examples!  Observation: The grass on the school’s front lawn is wet.  Possible inferences:  It rained.  The sprinkler was on.  There is dew on the grass from the morning.  A dog urinated on the grass!  All of these inferences could explain why the grass is wet. They are all based on prior experiences. We have all seen rain, sprinklers, morning dew, and dogs going to the bathroom.

Here are some examples!  Observation: the school’s fire alarm is going off.  Possible inferences:  The school is on fire.  We are having a fire drill.  A student pulled the fire alarm.  Again, these are all logical explanations for why the fire alarm is going off.

Observation Record 3 observations about your science classroom

List 3 inferences based on your observations

Scientific Models   A scientific model is a representation of an object or event that can be studied to understand the real object or event.  Examples include ball and stick models in chemistry, drawings of sound waves, and computer models of car designs and weather patterns.

Mystery Tubes  Observe the teacher’s Mystery Tube.  Write down what you see and draw a picture.  Write your prediction or inference of what is happening inside the tube.  With a partner try to make a model of the mystery tube.  When done, check with real Mystery Tube to see if you were right!