In this lesson students continue to think about solubility through graphing solubility curves for two substances and learning about the factors that affect solubility through notes and an activity.
For this lesson each student needs 3 m&m's.
To begin this lesson I give students an opportunity to review what we have already learned about solutions in terms of solubility and solubility curves. Solubility curves is a topic that many of my students have a hard time understanding so this activity gives them another opportunity to work with this difficult concept.
During this portion of the lesson I introduce students to the new topic for the day, factors that affect solubility. I present the new information to students on the PowerPoint while they take notes on the top half of their notes graphic organizer.
To help reinforce what students learned about factors that affect solubility I lead them in a tasty solutions activity.
The goal of this activity is for students to remember the factors that affect the solubility of a solid as temperature, stirring, and surface area.
I then explain to them, "We will be doing an activity to help you remember the factors that affect the solubility of a solid. I am going to come around with some M&M's. Just let them sit on your paper until we are ready to do the activity together. As I am walking around, read the instructions for the activity to yourself."
I then walk around and pour M&M's onto students' papers. Each student needs at least 3.
I then ask students if they are ready to start and have them take the first M&M in their hand. I put the TimerTools stopwatch timer on the projector and tell students, "we are all going to start together. When you feel that the M&M is dissolved, then record the time". For this first trial we are simply going to change the temperature so just let the M&M sit in your mouth. I then say 3, 2,1 and go. It takes students about 2 minutes to feel the M&M has completely dissolved. This introduction video shows how I begin the activity with one class.
As students are waiting I help them think about what we are doing by asking questions such as, "what is the solute? What is the solvent? What is the solution?" Here is a video of me questioning my students during the first trial.
After most students are done I say, "okay, now lets do the second trial. This time not only are we going to increase the temperature, but we are also going to stir." I then ask students if they are ready and then countdown, start the timer, and have them do the 2nd trial. This trial takes students about 1 minute. This movie shows how I do this.
Finally, I have students do the 3rd trial. I tell students that for this 3rd trial we are going to increase the surface area so we will be chopping up the M&M with our teeth. Then, I countdown, start the timer, and have students do the 3rd trial. This one takes them just a few seconds. This final movie shows how I get students started on this last trial.
As students are completing this last trial I tell them to spend some time answering the questions at the bottom of the activity. I tell them to try them on their own first, and that if they are stuck then they should work with their table groups.
After almost all students are done (about 5 minutes) I go over the answers with students. I do this by calling on students to share out their answers.
This is an example of a student's completed paper.