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March 2022 | Resource Feature
Cleaning Up the Lab
By Heather Lott
Instructional Strategies, Demos & Labs, Safety
|Figure 1. A messy lab workspace that hasn’t been cleaned.|
One of the best parts about being a chemistry teacher? Labs. One of the worst parts about being a chemistry teacher? Cleaning up after labs.
If you are anything like me, you have a love-hate relationship with lab activities. I am often jealous of teachers who do not have to spend any time cleaning up lab tables, washing glassware, or putting away chemicals. With the pandemic, teacher fatigue is at an all-time high, and some schools (like mine) are struggling to hire custodial staff … so teachers are being asked to clean up their own classrooms. If this had been the case when I first started teaching, I would have spent most of my free time cleaning up my classroom, and would most likely have gotten rid of many of my labs. However, I know that students need labs to learn how to be scientists.
Fortunately, I have found a way to put the cleaning responsibility on the mess-makers: my students. (Perhaps this will even carry over to other parts of their lives!) I do so by teaching a lesson at the beginning of the school year that addresses my expectations for a clean lab and logically call it, Cleaning Up the Lab.
I teach this activity after we do our lab safety lessons as part of my introductory unit, and before we do any other lab activities. When students learn first how to properly handle chemicals and glassware, we do not run into any avoidable problems later on.
This activity usually does not take up an entire 50-minute period, so I have an online assignment that students need to complete after they are done. This allows students to take their time with the cleaning if they need to, but by keeping the faster students busy, it also helps with classroom management.
The purpose of the activity is to teach students the standard cleaning procedure for which they are responsible, following the conclusion of every lab we perform. It starts with cleaning up their workspace and ends with washing their hands. In this activity, students work in pairs to create their own mess and then clean up after themselves using this procedure.
|Figure 2. A messy lab workspace that hasn’t been cleaned.|
At the beginning of the activity, students have to locate various commonly-used items around the classroom — including electronic balances, distilled water bottles, and weigh boats, among others. Using an electronic balance, they weigh a specified amount of solid (salt works best for this lab, as it is easily swept up, really cheap to buy, and nonhazardous!). Then they transfer it to a beaker, and dump it out on the lab table. (Most students reread this step to make sure they understood it correctly.) After creating their mess, students then use tabletop brooms and dustpans to sweep up their solids (see Figure 2). These are lifesavers — I suggest checking your local dollar store and stocking up!
Once the spill is cleaned up, students focus on their glassware. I tell them which piece of glassware they need to get, using the actual name (e.g., a 250 mL Erlenmeyer flask), and require students to find the glassware themselves so they can associate an image to the name. Each student is responsible for cleaning that piece of glassware along with the scoopula used for the salt. (This is a great way to ensure your glassware is clean at the beginning of the year before you start labs.) For my classroom, students are required to scrub the glassware inside and out with a scrub brush and soap, then rinse with tap water followed by distilled water. I am pretty picky about how glassware is cleaned, so this is a great way for me to monitor students to ensure they learn the procedure correctly.
After students have cleaned their glassware (and spilled a sufficient amount of water on their lab tables), they work on cleaning their lab area. For my classroom, this means that all lab materials are to be put away properly — and only then do the students clean the lab table. One student wipes down the table with a wet washcloth (using an “S” motion to pick up any solid) and another student follows with a dry paper towel to wipe up water and prevent water stains. This step has become more important lately, as we only have one full-time custodian for our school, and my lab area does not get cleaned. The more cleaning my students can do after their labs, the less I have to do later.
Once the students have cleaned their glassware and lab area, they need to focus on themselves. This starts with students cleaning their glasses or goggles with an alcohol solution and lens wipes and putting them away. I have students use VisionAid Rainbow II Liquid Cleaner, but there are other products that achieve the same results. After cleaning their glasses, students wash their hands and return to their seats.
Since I have implemented this process, I have noticed that my lab area is significantly cleaner. The lab tables are (almost) always clear of dust or spilled chemicals, and the glassware is clean. However, as with all things, students can become complacent. If I notice my students are starting to get lazy when it comes to cleaning glassware, we reference this lab handout and review the proper washing procedure. In most instances, this solves the issue; however, if your students are resistant to this process, you could make it part of their lab grade. Students keep the Cleaning Up the Lab handout at the front of their binders with their safety contract and syllabus for reference throughout the year.
This activity also addresses other procedures I have in my classroom. Since students are required to wear safety glasses or goggles, the conversation naturally comes up as to when it is appropriate to wear glasses instead of goggles, when eye protection is unnecessary, and what constitutes personal protective equipment in the chemistry lab. This means that they have fewer questions about these topics later in the year.
Another small “win” for this activity is the way it teaches students to find materials on their own. Usually, I am rushing around getting things set out for a lab before the students are ready to begin. I also believe some materials should not need to be set out every lab (e.g., safety glasses, balances, scoopulas). Since students are asked to gather several materials for this activity, they are forced to look for each one. This makes my life so much easier when I forget to put something out, and also encourages students to be independent.
This activity also refreshes students’ memories about how to properly weigh out a solid. Although they normally have done this before they get to my class, I am able to address things they may have forgotten, like not putting the solid back into the container when finished, or the importance of using a centigram balance.
Every chemistry teacher has their own procedures for cleaning up their lab areas (or, in a lot of classrooms, desks). This activity can be modified as needed to fit your classroom needs.
Not all classrooms have designated lab areas, so processes like hanging washcloths are not always possible. During the height of the pandemic, I used paper towels for wiping down the tables, so that they would not be reused by multiple students. This also cut down on the laundry that needed to be done when multiple washcloths were being used. Since then, I have switched back to washcloths to minimize the number of paper towels used.
If you do not like the idea of using an alcohol solution to clean student goggles, there are several other options available. One inexpensive solution is to use a dilute bleach solution. If the glasses are plastic, soak them in the bleach solution for one minute before rinsing and drying them. This does a great job of sanitizing, but does break down the plastic over time.
When I first started doing this activity with my students, I was hesitant to spend an entire day on something we could learn as we worked through labs. However, I now realize that the extra time spent on the procedures earlier in the year saves me time (and headaches) later. Once students have cleaned up after a few labs, they are able to move through these steps very quickly. Since my lab periods are only 50 minutes long, this helps ensure that students are not leaving dirty lab areas for me to clean up. Along with teaching students how to clean up the lab area for safety reasons, it helps teach independence and basic housekeeping skills. This activity has become a staple in my “Beginning of the Year” unit.
(article cover) Ant studio/Bigstock.com