Lab 20 aka Check the Solution!

Last night I had the opportunity to do another lab that I wrote with my students.  It is so exciting to see something go from words on a screen to a group of students working together in a laboratory.  I learned so much as I walked around the room last night.  Here are a few highlights:

~ I need to include facilitation of the pre-lab in my instructor’s notes.  I don’t think about how I’m going to facilitate until I’m about to do it!  This has been a challenge for me in the past, now that I have more experience I can handle it better.  I need to be able to think ahead for my writing so that I can be consistent in the facilitation, not just for myself, but for others who may end up using the lab, too.

~ Some of my directions are terrible!  It seems so clear to me, but half of my students messed up an important section.  I helped them go back and correct the issue and told them it was my fault, not theirs!  I will be more specific when I edit that section.

~ My students got it (maybe)!  One of the goals was for students to be able to calculate the unknown molarity of HCl using titration with a known concentration of NaOH.  And, by the end of the lab, students calculated the correct concentration of HCl!  Yay!  Now, we will see how that carries over onto their formal assessment . . .

~ I noticed I was asking students a lot of questions during the post lab.  I asked them to explain various observations, data, calculations, and the meaning of their answers.  I am going to include those in the post lab for the future.  I think these kinds of questions are very important as they guide students in their learning.  Do you ask leading questions to help your students?  Are there any questions you find yourself repeating on a regular basis?

All in all, I am even more excited about these labs and ready to move forward and test more of them this summer!   Do you have any projects you are working on?  Let us know how it is going!

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Comments 3

Allison Tarvin's picture
Allison Tarvin | Sun, 04/19/2015 - 11:44

What a relief to hear that your instructions are a little imperfect the first time, too!  What kinds of mistakes did the students make?  Titrations are a challenge with my students, too.  We are just about to begin our solution and acid base unit.

Geraldine Fsadni | Sun, 04/19/2015 - 13:40

It is true that titrations could be challenging to students. Recently I have been asking the students to perform online simulations of titrations.

This seems to help a lot when they come to the lab to actually carry out the titration.

Geraldine Fsadni

Chemistry teacher

Archbishop's Seminary





Sarah Kong's picture
Sarah Kong | Mon, 04/20/2015 - 07:57

Hi, Allison!  Here was the big mistake: I gave my students enough acid to do several trials.  They needed 15 mL per trial.  Half the class began their first trial with all of their acid.  I need to make my instructions clear so they know they have a beaker full of acid and they are to measure 15 mL out of that beaker into another beaker for each trial.  Thankfully, I had plenty of acid and just gave them more.  They did a fabulous job after that!  Thank you for sharing; I hope your acid base unit goes well!!