{"id":5592,"date":"2016-11-29T15:24:35","date_gmt":"2016-11-29T21:24:35","guid":{"rendered":"https:\/\/www.kabt.org\/?p=5592"},"modified":"2018-10-31T09:53:08","modified_gmt":"2018-10-31T14:53:08","slug":"teaching-quantitative-skills-using-the-floating-disk-catalase-lab-intro","status":"publish","type":"post","link":"https:\/\/www.kabt.org\/?p=5592","title":{"rendered":"Teaching Quantitative Skills using the Floating Disk Catalase Lab: Intro"},"content":{"rendered":"

I find it remarkable how deeply the biology education community has embraced the call to increase quantitative skills in biology. \u00a0 This is certainly not an easy change to incorporate into our curricula and it is one that the community will be working on, tweaking and improving over time as our own instructional quantitative strategies and skills mature.\u00a0 But even with this willing effort by the community where does one find the time to add “something else” to an already packed curriculum? \u00a0 The first part of the answer to that question is to first have confidence that it can be done; \u00a0the second part of the answer has to do with strategic and efficient curriculum decisions; and the third part of that answer is to realize that, like our students, we are somewhere on learning progressions ourselves and that our skills and understandings will deepen the more we teach quantitative skills.\u00a0 No one has time to teach all the biology they would like to teach.\u00a0 Every year most of us make all sorts of decisions about what to include, what to emphasize, and what to leave out.\u00a0 The challenge of adding structured instruction in quantitative skills is daunting, particularly since most of us have not had time to develop our own math-based pedagogical tools and skills.\u00a0 With that in mind we often fall back on the type of math instruction that we likely encountered in our own educational background.\u00a0 If, like me, most of your math instruction was based on algorithms and focused on getting answers instead of learning how to do math, then likely if we model our quantitative skill instruction on the math instruction we experienced, we won’t be doing a very good job helping our students develop quantitative skills.\u00a0 Instead, perhaps we (the biology teaching community) should consider delivering quantitative skills instruction in a way that models effective and efficient math instruction informed by research.\u00a0 Here’s the good thing–it turns out that many of the strategies that work well for teaching science also work well for teaching math.\u00a0 We biology teachers just need a bit more experience trying to explicitly teach appropriate quantitative skills.\u00a0 We need to develop our own specialized pedagogical content knowledge. \u00a0 I thought I’d put out an example of how this might work in a classroom–certainly not as an exemplar but more as a starting point.<\/p>\n

<\/div>\n

To this end, at the 2016 NABT meeting Jennifer Pfannerstil, Stacey Kiser and I shared strategies to introduce quantitative skills focused around a classic lab: The Floating Disk Catalase lab. \u00a0The earliest version of this lab that I know of was published in ABLE.
\nA Quantitative Enzyme Study Using Simple Equipment by Beth A. D. Nichols and Linda B. Cholewiak.\u00a0<\/a>\u00a0 Yes, that is the same Beth Nichols that recently retired from ETS but has worked with so many in this community.<\/p>\n

<\/div>\n
In this series of posts I’ll walk through the material we presented at NABT along with some discussion on the rationale of each example coupled with resources so that you should be able to design your own lab that structures quantitative skills. \u00a0A caveat: \u00a0I want to emphasize how rich this particular lab is for developing quantitative skills–in fact I’ll present more possible ideas than probably anyone will want to use in any particular class. \u00a0So pick and choose what works for you and your class but consider the examples presented here as something to shoot for with your students. \u00a0Let’s get started.<\/div>\n
<\/div>\n
\n

Lab Overview: \u00a0<\/b><\/p>\n

\n
<\/div>\n
If you are not familiar with the lab it features a simple and student friendly method to measure\/quantify enzyme action or kinetics using disks of filter paper soaked in a yeast solution as the enzyme source and a solution of hydrogen peroxide as the substrate. \u00a0Here’s a write-up by Paula Donham on the technique: \u00a0https:\/\/www.kabt.org\/wp-content\/uploads\/2009\/02\/catalase-enzyme-lab.pdf<\/a>\u00a0 Note that one of the educational goals that Paula used this lab for was to introduce the use of box plots as a way of presenting your data. \u00a0(That’s a quantitative skill, btw.)<\/div>\n
<\/div>\n
The materials:<\/div>\n
<\/div>\n
<\/div>\n
<\/div>\n
<\/div>\n
How does it work?<\/div>\n
<\/div>\n
Dip the paper disk in the yeast solution. \u00a0The yeast solution provides a set amount of catalase per disk. \u00a0Drop the disk into a solution of hydrogen peroxide.<\/div>\n
<\/div>\n
\n

<\/p>\n<\/div>\n

<\/div>\n
The catalase breaks down the hydrogen peroxide into water and oxygen. \u00a0The oxygen bubbles catch in the paper fibers and eventually cause the disk to rise. You can see the disk staring to rise in the lower right hand corner of the cup.<\/div>\n
<\/div>\n
\n

<\/p>\n<\/div>\n

\n
I use the plastic cups to make a dilution series with the hydrogen peroxide and the 24 well plates for the testing. \u00a0The well plates allow you to put one disk per well (which might lead to better precision).<\/div>\n
<\/div>\n
<\/div>\n
<\/div>\n
Ready to collect data with eight data points per substrate dilution:<\/div>\n
<\/div>\n
<\/div>\n<\/div>\n
<\/div>\n
Here’s a short video of the procedure using the well plate:<\/div>\n
<\/div>\n
<\/div>\n<\/div>\n<\/div>\n