laboratory instruction

Acid, Base, pH and Food Chemistry

I try to examine activities an multiple levels. First on the list, I want to know if my students will be engaged and learn something. Second, how difficult is it for me as a teacher to actually pull it off? One of the most important questions...are the students learning chemistry or just having fun? This is the first year I have attempted the following activity.  Students were engaged in the real world connection, they asked questions, it transitioned into some chemistry concepts and even some parents got involved. The activity involved acid, bases, pH and food.

Who inspires you?

This blog post may be a bit non-traditional, but in this submission I recall a memory from early in my teaching career when my dad (who was an environmental chemist) visited my classroom. The day remains embedded in my memory bank, and had a profound impact on how I view labs - as an opportunity to extend the learning.

Titrations and Microscale Chemistry

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.

Chemistry in a Bottle

Are you familiar with the dynamic density bottle experiment? This interesting experiment was invented by Lynn Higgins, and is sold by various science supply companies. Two immiscible liquids (usually salt water and isopropyl alcohol) and two different types of plastic pieces are contained within a dynamic density bottle. The plastic pieces display curious floating and sinking behavior when the bottle is shaken. 

Compiling Student Data

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.

Shorten Grading Time with this Stoichiometry Tool

As many chemistry teachers know, grading lab reports can be a very time-consuming task. For me, the lab report that has required the most time to grade is a stoichiometry lab that I have been doing the past couple years. Though we do at least four “formal” lab reports each year, what makes this one different is that it involves a lot more calculations and subsequent results than any of our other labs. Regardless of how well they organized their report or wrote their conclusions, their results need to be checked for accuracy. This takes time. Even after eventually being able to generally eyeball their work, it still takes more time than I would like. So, this year I finally decided to sit down and generate a tool for me to expedite this process—the stoichiometry calculator.

Hydrates Take 2

My students and I tend to have good experiences with a hydrate inquiry lab that I have "tweaked" (see the previous blog). Essentially, my students have some practice with hydrates in the lab and then they are provided an unknown hydrate. They must separate off the water by heating and calculate the mass of the anhydrous salt and container before they come up and put it on the scale. As an added twist, they must also ask me a question about what information they need from me to calculate the mole to mole ratio of the salt to water.

AP Chemistry Lab Notebook Structure

How do you support growth in your students’ writing and communication over time? There are so many things: Claim, Evidence, Reasoning (CER) scaffolds, sentence starters, and more. How might all of these tools used in introductory courses come together in an upper-level course? In this post, I will focus upon my AP Chemistry lab notebook set-up.