I allowed my students to choose between two separation type laboratories. About two thirds of the class chose to separate the flavoring out of a grape of cherry soda. The rest of the students used paper chromatography to determine if red-40 dye was in a specific type of candy.
As I began to prepare my labs for this upcoming year, I decided to put a bit of a twist on a previous density of a block lab I had used in the past entitled the Measurement Challenge that is sold by Flinn Scientific. It can also be used to find the mass of a block given the materials density and requiring students to measure and calculate the blocks volume. My added twist resulted in great scientific discourse.
The Flinn website sums up their software with these sentences, "Flinn’s Online Chemventory™ Inventory Management System(link is external) is a cloud-based lab management system that allows multiple users on multiple devices from multiple locations! Available as a 1-Year, 3-Year or 5-Year license.
The ACS Committee on Chemical Safety has released the 8th edition of "Safety in Academic Chemistry Laboratories". The publication provides advice for first- and second-year university students.
As we all know, research and general educational practice clearly indicates that students learn science best by doing it – not just reading about it. Hands-on, process and inquiry based science is the key to understanding science. Unfortunately, this is a double edged sword for science teachers in that doing science has its potential hazards and resulting risks. Science laboratories, classrooms and field work sites can be unsafe places to teach and learn. If a student gets hurt while doing an activity in the lab, in the field or even at home if it was a teacher’s assignment, there is potential shared liability for both the teacher and the school.
Organizing lab equipment.
Near the end of the school year we are all thinking about what we will do with our AP Chem students until the end of the semester. Last year I wrote about a post AP independent study activity that I use dealing with transition metal compounds. I still like it and use it. But this year I want to talk about a very involved lab that many of my colleagues are ignoring.
I tend to enjoy acid base titrations for several reasons. First, students get to work with burettes, acids, bases and they see a nice "color change" when they reach an endpoint. Many times, students who tend to struggle with pen and paper testing excel at the "hands-on" approach. Titrations also dovetail well with stoichiometry which provides a nice review of information closer to the end of the year.
To assist in grading the lab results for this and other quantitative labs that we did, I created Excel spreadsheets where the students’ results could be entered. The spreadsheet then did all the required calculations and compared the students’ results to the theoretical value. This made grading the lab reports much quicker and more accurate, flagged incorrect student calculations, allowed a much more complete discussion of the lab results and permitted “what if” questions to be discussed.
The ACS Committee on Chemical Safety has published new Guidelines for Chemical Laboratory Safety in Secondary Schools. This document is organized with the R.A.M.P. concept – Recognize the hazard, Assess the risk of the hazard, Minimize the risk of the hazard, and Prepare for emergencies. The online document includes two pages for each letter that could be printed and posted in the classroom to reinforce these principles of safety. The documents are provided to strengthen the safety practices of teachers and help them to promote a culture of safety that their students will take with them throughout their academic and professional careers.
