Many times, when students are making observations, they add inferences into them based on what they think their sensual input is telling them. It is sometimes difficult for students to differentiate between the two, but it is a very important difference for them to understand. This lesson helps students to understand the difference between observations and inferences and teaches ways for students to resist the temptation to make inferences when they are observing scientific phenomena.
Have students sit on the floor in a circle, with their science notebooks, and ask them to share what they observed in yesterday’s lesson. Some things student might share are: bubbles formed on the rocks in the cup of vinegar, the inscription on their sidewalk chalk was muted or rubbed off, the sand was rough and the chalk was smooth and powdery, the vinegar smelled disgusting, etc.
I tell students that making observations is a very important part of science. It involves using the senses and recording what they tell you about something. I tell students that observations are merely a record of what is sensed by your five senses. There is no opinion added to the information. There are two different kinds of observations: quantitative and qualitative. Share PowerPoint slides 2-3 with students.
Quantitative observations are those that involve numbers, such as: there are three eggs in the nest, or the rock is one inch long. Quantitative means anything that can be counted or measured.
Qualitative observations are those that may be difficult to describe in numbers. They include the characteristics of something such as smells, taste, or colors.
At this point, I share with students that when scientists make observations, they notice what is going on in the world and they become curious. They begin to try to make logical conclusions about what is happening based on their observations. The dictionary defines inferences as: a conclusion reached on the basis of evidence and reasoning (dictionary.com, 2014). Inferring is a good exercise, but should not be done without all the evidence in-hand. Students often jump to inference with too few observations. Share PowerPoint slides 4-5
I tell students that, today, we are going to practice making observations and see how inferences are affected by observations. Students will glue their observation sheet into their notebooks, prior to beginning this activity.
I walk students through PowerPoint slides 8-10. Be sure students have time to make their observations and inferences as you show the different panels of the footprints.
Now it’s time for students to practice making observations and inferences on their own. Hand out a second observation and inference sheet to students. Have them glue them into their interactive science notebooks.
Ahead of time, I make 10-15 bags of mystery items in brown paper bags. Number the bags and have a key for yourself, handy, but hidden. In these bags, place items such as a CD, paperclips, modeling clay, gravel, raisins, coins, toothbrush, paintbrush, marshmallows, dice, scissors, and candles.
I walk students through PowerPoint slides 11-12, to set up the expectations for the rotations. Give students 5 minutes at each table to observe the contents of two bags without looking inside. Students must record their observations on their observation sheets in their interactive notebooks. Based on their observations, students must make an inference about the contents of their bags. At the end of five minutes, I have students move to the next station in a clockwise fashion.
When students have completed all rotations, I display PowerPoint slide 13 while calling them back to the floor to share what they observed and inferred.
I allow students to share their inferences allowed before revealing the contents of each bag. This is a fun time as students either roar their success or groan their despair at making an incorrect inference.
To close this activity, I remind students that while inferences are an important part of scientific investigation, they should be reserved for the discussion section of an experiment or demonstration. During an experiment or demonstration, only observations should be recorded. These must be verifiable.
Students will record their observations and inferences in their interactive science notebooks. These two sheets will serve as assessment of understanding and participation in the two activities for this lesson.