As high school teachers, we know that understanding how measurement works is crucial for lab skills and for understanding significant figures. We think measurement should be an easy topic for students to learn; especially because we know that teachers begin working with students in elementary school to teach these skills. However, I, and many other teachers, have spent countless hours teaching and reteaching a seemingly simple skill.
A simple laboratory experiment in which students simply measure the wavelength of light is described. An LED light, diffraction glasses, and a meterstick are the only required materials.
Erica Jacobsen shares highlights from the October 2017 issue of the Journal of Chemical Education that are of special interest to high school chemistry teachers.
I want to share a measuring activity for you to consider. First, start with two baseballs. The first baseball is a regular baseball. The other baseball is called a "small ball". Next, get six to eight students to volunteer. Without talking at all the students must hold the normal baseball and the small ball. They then must decide if the normal ball has more, less or the same mass as the small ball.
My first experiment involves measuring the density of water. Each group of two kids is assigned a specific volume of water from 10 to 100 mLs on the tens. They simply measure the mass of an empty graduated cylinder and then add the water and find the mass again. Once they have their data they go around the room and find another group that has one of the volumes that they need and get the data from them and record their names. Once complete they generate a graph of the data and answer a few simple questions. The whole procedure can be completed in about 20 minutes.
Sharing the topics of measurement and the metric system could at first thought be seen as largely a visual endeavor. Students might measure the lengths of various objects and then convert their results from one metric prefix to another. Ditto mass or volume, with their respective measuring tools. What if the sense of touch could be incorporated to provide a different aspect of learning, beyond simply manipulating the objects?
In a dramatic movie trailer voice: “The Boiling Point. Gone without a trace. Or were they? The scene… a mystery. Had they disappeared? Been broken up into unrecognizable pieces? Can our hero find the answer? Or will it be too late?”
Students who are tired of "pen and paper" work now get to get up and use their answers to mass something or find the volume of something and see if they are correct.
Historically, my students report significant figures as one of the most confusing concepts in honors chemistry. My recent blog post described the process of transforming my introduction into an inquiry activity. I’ve also re-worked my practice activities to be more directed to specific student needs, more focused on spending time with small groups, and more dedicated to active learning. This four step tiered plan works for me.
Education “buzz words” can be meaningless jargon, or they can challenge us to consider new approaches to teaching and learning. Don’t let the jargon be a buzz kill!
“Significant figures are so confusing,” says my former student, who is currently taking AP Chemistry. My PowerPoint lecture with lab to follow didn’t work. Convicted, I wrestled with transforming my tired lesson. I embraced the buzz words. Let’s look at a significant figures lesson that changed my compliant, quiet learners to ENGAGED COLLABORATORS.