Every biology class utilizes an organic compound identification lab; for me, this is one of the best. By slowing down to introduce the lab equipment and safety as a separate lesson rather than a quick reminder at the start of the lab procure day, we engage student curiosity and allow them to fully digest the many complex test procedures they will be following.
Adding in a student choice day engages students and makes things more personal for them which creates a very positive, collaborative, and inquiry based lesson day where we work together to figure out how to work with our diverse samples and asses the accuracy of our results. And finally, giving students an opportunity to share out their original data as a class allows them to critically compare and analyze data against their prior knowledge and come up with interesting questions they'd like to investigate in the future.
The lab is broken up into a five day series:
During Day 1, students complete a pre-lab activity and explore the equipment, procedures, and safety guidelines for the series. Standards: W.9-10.1, SL.9-10.1, SP1, SP3, SP4, SP8, XC-SF-HS-2
On Day 2, students focus on the lipid and saccharide tests for five samples. Standards: SL.9-10.1, SP1, SP3, SP4, SP8, XC-SF-HS-2
During Day 3, students focus on the protein and starch tests for five samples and brainstorm their own group samples to bring in for testing. Standards: SL.9-10.1, SP1, SP3, SP4, SP8, XC-SF-HS-2
During Day 4, student groups work to test their own five samples. Standards: SL.9-10.1, SP1, SP3, SP4, SP8, XC-SF-HS-2
And on Day 5, we come back together as a large group to assess our lab work results and review the major concepts of the series. Standards: W.9-10.1, SL.9-10.1, SP1, SP3, SP4, SP8, XC-SF-HS-2
1. Ask students to take out their lab document and turn to page three with lab procedures for the two tests they will be focusing on today: starch and proteins.
2. Show the lab equipment to students again and indicate where they can find any necessary materials.
3. Take any questions students might have from yesterday. Review chemical/reagent safety as outlined on my brief powerpoint slides.
4. Time for students to get to work! Check out the organic chemistry lab tips and tricks document for suggestions about ways you can better support your students as they complete their lab session activities.
1. Remind students to take time to discuss their data and compare it to their predictions within their lab groups.
2. Field clarifying questions as you move around the room. Students will typically focus on issues about clean up and the logistics of their written lab report more than anything else--the lab procedures are very detailed and you will find that the pre-lab process sets students up for success on many levels throughout the lesson series.
3. Students will be filling out their data table as you can see in this student sample, answering the summary questions on their lab document, and discussing the specifics of their written lab report responsibilities. I find that because there is quite a bit to digest and plan for in preparation for tomorrow's culminating lab activity using samples each group brainstorms and collects for analysis, students are on task within their groups throughout the session and redirection from me as the teacher is minimal.
1. Announce that tomorrow students will be testing substances of their own choosing. Ask each group to brainstorm four substances they will bring in for testing tomorrow.
2. Tell each group that they will need to get their four substances approved by you and record them on this class document.
3. Hand out this lab extension document for student groups to record their predictions for each of their chosen substances.
Now on to Day 4!