In this lesson students are introduced to solutions through performing a lab activity. The goal of this lab activity is to give students a chance to make some solutions so that they have something visual to think about as we discuss solutions. The goal is also to give students an overview of what we will be learning about pertaining to solutions.
For this lesson there are several resources needed for each group:
To begin this lesson I pass out the unit8 intro lab to students and have them quickly look over to themselves.
I then tell them, " We are going to be starting our new unit today which is all about water quality. In order to learn about this we need to first understand what solutions are. The goal of this lab activity will be to make some solutions and then analyze them both qualitatively and quantitatively."
I tell students that they are going to be making four solutions and that the instructions are clearly written for them on their papers. I choose not to go over the details of the lab with students because this is fairly straightforward lab in terms of procedures that they should be able to figure out with their groups. This practice helps students to become more independent in the lab.
I tell them that once they are in their groups to make sure follow the instructions and to keep their solutions until they are done with the entire lab.
I then break students into cooperative groups and have them start the lab. See my reflection about cooperative groups for details on how I do this in my classroom.
In this section of the lesson students are actually performing the unit8 intro lab at their stations with their groups. I tell them to make sure to use their calculators and that they will also need their periodic tables.
The students start by making four solutions (A-D). They then analyze the solutions both quantitatively and qualitatively by answering questions about them. Although students have not seen the equations before for the quantitative part, I find that they are able to figure them out with their groups, and some additional help from me if needed.
As students work they make sure to take on their roles within their cooperative group. This means that one student is keeping others on track, another student is reading the procedures and questions, a third student is doing the lab, and the fourth student is cleaning up.
Also as students work I walk around to make sure that the lab makes sense, check students answers, and keep students on track.
Here are some videos which show me doing this:
As students complete their labs I have them wash their test tubes out in the sink and work on their vocabulary that they received after the last exam. This is an example of one student's completed vocabulary.
The nature of this lab is to allow students to begin to explore solutions so I do not grade it as a formal lab. Rather, I grade this lab when I check their binders at the next binder check (at the end of this unit). I grade based on 20 points and just take points off if they are missing sections. For example if they only have half of the lab done they get 10 points.
Most of the students earn all of their points. Those students who do not are usually missing the last part of their lab because they simply did not take the time to complete their analysis of the solutions in terms of concentrated/dilute or saturated/unsaturated/supersaturated.