This is the first lesson in a series of lessons designed to assess/review students’ ability to design comprehensive and grade level proficient lab investigations, something they will be expected to do quite often over the year. These lessons will target the following NGSS science and engineering practices and can be done individually or combined together depending on the level and experience of the students:
Prior to teaching this lesson, I looked through my storage cabinets and collected as many random objects as I could find that I believed students would be able to use as the focal point of an experiment. Items included drinking birds, friction blocks, pulleys, building blocks, constant velocity cars, non-motorized flat top cars, springs in a variety of tensions, small bouncy balls, and a variety of other random objects. I have eight lab tables so my goal was to find at least 12 objects students could choose from for this activity
Have one student from each lab group pick an object from "the box of random objects" (I like to say that phrase in the voice used in the Nickelodoen show iCarly when they introduce their bit "random dancing" while I do some random dancing of my own, just to be silly since the students love references to their pop culture. Here is a link in case this is unfamiliar.) TEACHER NOTE: I do not tell students what they are picking the object for since I don't want them to choose something because they think it will be easy to design an experiment around; I want them to pick something they find interesting on its own.
When all student groups have an object, we go over the Describe An Experiment We Can Do PowerPoint that has pictures of a few items that are NOT part of the box of random objects. As a class, the students brainstorm how the pictured objects might be used as the focus of an experiment. NOTE:Students are not making testable questions at this point, but are very briefly describing an experimental idea.
As students generate ideas I push them to make sure their experiments are appropriate for an 8th grade level so they know I am looking for an experiment that (1) they have not already done and (2) challenges them to learn something new.
When student answers are consistently interesting, creative and grade level appropriate, I allow them to discuss 3-5 ways the object they chose from the box can be used as the focus of an experiment. As they finish their list, I have them put a star next to their two favorite ideas.
Common Core Connection: Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 8 topics, texts, and issues, building on others' ideas and expressing their own clearly.
Students are going to be working in groups a lot over the course of the year. As students are discussing ways to experiment with their object, I am walking around making sure that all students are participating in the discussion, everyone is actively listening to their group members and adding to or tweaking other's ideas.
I next introduce students to the concept of a testable question. This should not be a new concept for students. However, I anticipate that they will have very limited experience with writing their own testable questions.
I explain to students that the goal of a testable question is to lead to an actual investigation and should not be answered with a simple yes or no. While I don't go into specifics about independent/dependent variables, I do explain that testable questions should be written in the form of changing one thing to see how it affects something else. Using the PowerPoint What Is A Testable Question, students practice changing general questions into testable questions.
Students work as a lab group to come up with three possible testable questions for each of their favorite experiment ideas generated earlier during the warm up (marked with a star). As students are working, I walk around and monitor for potential problems, such as the question being written at too low a level, a question they have already tested during 6th or 7th grade, or if necessary materials are not available. NOTE: I do not look for accuracy in wording at this point. I believe that students learn best when they make mistakes and they will notice their wording is wrong if they cannot identify what they change or what is affected by that change during the next step.
Next students attempt to identify the different variables. I direct them to put a box around the independent variable, and underline the dependent variable for each of their questions. Students should have a good working knowledge of these words since many of them designed an independent science investigation at the end of their 7th grade year. If the groups do not have any idea what to do, I direct them to identify what is changed and what is affected by that change within their question and to guess at which is the independent and dependent variable. This allows me to informally assess student understanding prior to the next lesson on variables and allows students to determine if their questions are written in the proper format.
Students will identify their top two testable questions and either highlight or circle them so I can easily identify what they are planning.
Again, as students are working I am monitoring that all students are participating in an effective manner and building on each others ideas.
Student groups complete the Testable Question Checklist to determine if their questions meet the necessary criteria. If it does, they turn in the checklist for approval. If not, students rethink their ideas and complete another checklist with those questions. This allows students to self assess their work and make necessary corrections prior to turning it in for review. I want students to begin to recognize that it is perfectly acceptable to make mistakes and that the opportunity to correct errors is always there for formative learning assignments.
One final note, students will ask good questions when given both the opportunity and directive to do so. The following video describes a technique I have started using to help students become more natural question makers in their day to day lives as well.