Indicator Activity - Assigning Roles for Students in the Laboratory

This lab activity is designed to allow students to explore the use of indicators. It serves as an introduction to acids, bases and pH.

Every time we do a lab, students are assigned a role within their group (see figure 1). I have role descriptions on cards and depending on the lab and the class I either have them self assign or I assign the roles within each group. I have the students identify the role that they played on the lab sheet they turn in. See the Teacher Document PDF for a printable set of cards.

Figure 1: Student roles for laboratory work

Students will determine their own procedure steps given three prompts and the materials they are provided. If you provide the student with a digital document, they can add photos for each problem. See figures 1-3 for student photos for Problems 1 and 2. Additional student photos are shown in the Teacher Document found in the Supporting Information. I allow students to take pictures on their phones and add labels using snapchat/instagram, but if you are not comfortable with that or have a no cell phone policy you can have them bring them up to show on a document camera/projector.

Table 1: Common Acid-Base Indicators¹

^{STUDENT PHOTOS} 

Problem #1

Figure 1: Methyl Orange results in pH 1, 3, 5, 7, 9, 11

Figure 2: Phenolphthalein in pH 5, 7, 9, 11

Problem #2

Figure 3: Universal Indicator results in pH 1, 3, 5, 7, 9, 11, 13

Student and Teacher Documents can be found in the Supporting Information when readers are logged in.