Differentiate observation from inference (interpretation)
Differentiate observation from inference (interpretation) and know scientists’ explanations come partly from what they observe and partly from how they interpret their observations.
All science process skills ultimately depend on the ability to make accurate observations. While observing seems simple, it is much more difficult than most people realize. As one indicator of its unexpected complexity, think about court trials that feature conflicting testimony from first-hand witnesses.
Observing requires focusing attention, which many of us find difficult to do. It also requires deciding where to focus the attention. Skillful observing often requires training and experience with a topic to know which senses to use, where to aim those senses, and what clues to seek with those senses. Observing includes all the senses, not just vision!
As a recent true-life example, my house has a problem with flickering lights. An electrician came, noted the symptoms, went to the main power box, and tested the tightness of some connections with a screwdriver. Then he said, “There’s the problem. Look at the corrosion in that connection.” As a non-expert, I needed him to give me very explicit directions about exactly where to look and the color of the corrosion before I could observe it.
This example also illustrates the intent of this standard. The electrician observed a green coating on a particular wire junction. That was his observation. He inferred that this coloring was due to corrosion of the wire. He further inferred that the suspected corrosion was causing the flickering of my house lights. This last inference was based on combining observations (flickering lights in all rooms of the house, greenness on wire junction) and interpretations of those observations (problem at a central location, corrosion in main electric panel).
It is very important to learn to distinguish what we actually observe from the conclusions (inferences) that we make based on those observations. First, we often already have strong ideas about what we are going to conclude and therefore, what we are going to see. In order to accurately observe, we need to set aside our biases and let nature reveal its reality and complexity to us. We need to get as close to the objective truth that our minds and senses will enable us.
The second reason we need to distinguish observations from inferences is that we sometimes make mistakes in our conclusions. If we get information that makes us suspicious of our conclusion, we can go back to our original observations and determine if they can form the basis for a different conclusion.
It may help to practice distinguishing observation and inference on topics that have nothing to do with science. Think of all the possible inferences that might explain why someone laughs as she walks into a room.
Here are some examples that distinguish observation from inference for some of the topics in Grade 4 science.
Observation: The second light bulb went out when the first light bulb was disconnected. Inference: It is a series circuit.
Observation: The compass needle moved when I connected the battery. Inference: Electricity running through the wire created a magnetic field.
Observation: The plant watered with salty water is shorter than the plant watered with fresh water. Inference: Salt water is less healthy for this kind of plant than fresh water.
Observation: There is a mudflat at the mouth of this river. Inference: Erosion by the river brought earth from the hills to the ocean.
Note that inferences are never final. They must be consistent with all observations that have been made and will be made. A valid test of an inference generally involves making observations independent of those used to originally generate the inference.