In this lesson students have the opportunity to act as Forensic Chemists by performing a lab with common over-the-counter pharmaceuticals. This lesson comes from the Health and Science Pipeline initiative's (HASPI) Medical Chemistry Curriculum with some revisions. All of HASPI's lessons can be found on their website. I have found that theses lessons are a great resource to bring real-world applications to chemistry class. Through doing this students become more engaged in the lesson and better understand the importance of learning chemistry.
There are several materials needed for the lab including:
To introduce students to the lesson I have them answer two prelab questions.
These questions are found on the top of the first page of the lab.
I give students some time to think on their own first and then have them discuss with their groups.
I then call on the different groups to discuss the questions. This video shows how I discuss this with my students. Rather than calling on students individually, I will often call on students by group and then one student in the group will share out. I find this especially helpful when I give students time to discuss in groups. It is difficult to hear the students in this clip, but I repeat what they say for the rest of the class to hear.
In this portion of the lab I go over the basics of the lab.
This includes the following:
1. I tell students that they will be performing tests on four known substances and then use their data to determine the identity of an unknown substances. These tests include...
2. I also point out to them that they will be going to the conductivity station to determine the conductivity of the four known drugs and that they will not find the conductivity of the unknown.
3. I also let them know that they will not get the unknown substance until they are done with testing the first four.
I then break students up into cooperative lab groups. This picture shows the groups and how I have them rotate. I remind them that they should be switching roles throughout the lab. For more information about collaborative lab groups see my reflection from unit 1.
In this section students are actually doing the lab on their Lab Paper.
As students perform the lab I walk around and make sure that students are staying on task and all participating. I also look at their observations to make sure that they are recording appropriate information for the tests. Some of the most common issues students have include:
This picture shows the results of one group's tests. The amount of different colors in each of the wells gets students really excited about the lab.
This pdf is an answer key with the 3rd page containing the expected results for each of the well plates.
This is one of the few labs that I grade without a rubric. I basically give students points for having completed data and then for answering the questions.
This is a copy of a graded lab. Notice that the lab is worth 25 points total. Each of the questions is worth 1 or 2 points and the table is worth 11 points, 1 point for each row. If students are missing parts of the table I deduct .25 points for each missing box up to 11.
This particular student did well with answering the questions and only missed question number 6, "Why would the results from test #5 make a difference when you take over-the-counter drugs?"
- I was expecting an answer of how the drug may change the acidity of your stomach.
The other question that a lot of students struggled with was question number 3, "Why would solubility matter when taking a drug?"
- This student gave an answer that I was hoping for which was, "It matters because if the drug is insoluble then it won't dissolve when it is inside the body."