top of page

Tips for minimizing waste in science class

Updated: Jul 19, 2023

Science is messy. Experiments fail. Both are important parts of teaching and learning about science, but I struggle with the amount of waste this creates. Here are some tips for how you can provide ample experimental opportunities for your students without generating more trash than necessary.

science experiments and equipment waste AI art
Source - Tailwind


For several years now I've been on a personal quest to reduce the amount of plastic and trash I produce at home with my family, but shouldn't that include waste my students and I create at school as well? It's a huge downer to throw away a mountain of garbage after a successful lab, to the point where I've considered not doing certain ones anymore, but that's not really fair to the students. Instead, I've had to get creative. Read on to find out how you can do more with less.

Start a compost bin or a school garden

Lots of laboratory materials are hazardous, including chemical waste, metals, broken glassware, and so on, but plenty of things can be recycled on-site with nothing more than a compost bin or a hole dug in the ground. This includes most plant matter, paper, cardboard, and more.

The value of a compost bin can go way beyond the science classroom, of course. If you or your students are feeling ambitious, it could easily become a school-wide initiative to be used daily for recycling coffee grounds, lunch waste, or other compostable classroom materials. You can also add grass clippings or leaves from around the schoolyard to make some really good quality compost with minimal effort.

school compost made from food waste rooftop garden
Compost made from school waste for use in our rooftop garden

Now that you've got some compost, why not start a school garden to take advantage of it? You'll be able to grow healthy plants that you can use for eating or for class experiments. I wrote a previous blog post about how to start a school garden, and one about kitchen waste that includes a description of how to get started composting, so what are you waiting for?

garlic growing in school rooftop garden
Garlic growing in the school garden

Do demonstrations where appropriate

Whenever I plan a new lab activity, I ask myself if it really makes sense to get a class full of students to carry it out. If they will be practicing skills and techniques or designing some aspect of the experiment themselves, then yes, it is probably worth letting kids go at it. Conversely, if the goal is to observe a phenomenon in action or produce a desired effect of some kind, maybe I should just demonstrate it instead. A great demo can be just as engaging for students as doing it themselves, and you can be pretty confident that it will work out as planned (hopefully). In such cases, the focus is on asking questions, making predictions, and discussing results.

I like to demonstrate things like oobleck - the cornstarch and water mixture that behaves like a non-Newtonian fluid. Sure, I could let students mix and play with it on their own, but that would require a ridiculous supply of cornstarch. There's also a risk that they will get the ratio wrong and ruin a whole batch. Instead, I mix it myself and then get kids to try different things with it in front of the class. Students still get to poke and punch it, but we only make one container of waste. When we're done, I toss it in the compost bucket for use in the school garden.

oobleck cornstarch and water made in school science class
Oobleck (cornstarch + water) - take it outside to reduce the mess and compost it when you are done

Use less with microchemistry

Years ago I attended a workshop in the UK where one of the chemistry teachers could not stop talking about the benefits of microchemistry. For those unaware, this is a method used to conduct chemical experiments at a very small scale. Why use 50ml of hydrochloric acid, for example, when you could use 5ml instead? Depending on the equipment you have available at your school, you could potentially conduct experiments using microliters and milligrams of supplies, potentially saving your school a significant sum of money while generating a lot less waste.

Other benefits include improved safety, faster reaction and filtration times, and less space required for storing chemicals and glassware. It also requires students to measure very carefully, which is a worthwhile skill all on its own.

Consider the diffusion of potassium permanganate, metal displacement reactions, titrations, elephant's toothpaste, enzyme experiments, testing for the presence of macromolecules, and so on. All of these labs can be done with a fraction of the usual materials.

Metal displacement reaction in a well plate
Metal displacement reaction in a well plate

Once you start doing microchemistry, you'll constantly be thinking about the smallest scale at which you can conduct your experiments without compromising on the results. It's a great mindset to have when trying to reduce waste.

Conduct virtual labs

Nothing is more frustrating than spending a ton of time or money on an experiment only to have it fail miserably. Sometimes this is a valuable learning experience for your students, but it can also just be a colossal waste of resources and lesson time. Enter the virtual lab, guaranteed to give you useful results while saving on time, money, and materials (not to mention the lack of cleanup required!).

Of course, there is something kind of thrilling about students getting their hands dirty and actually trying an experiment for themselves, but do you really want to deal with the disposal of a class set of fetal pigs or a lengthy bean-growing experiment that failed because no one was there to water over spring break?

Years ago it was hard to find decent virtual labs online, but that's no longer the case. The University of Colorado's PHET website is packed with interactive labs and exercises for all science subjects, although most are physics-focused. Here's a great list of virtual labs for biology, and here's a similar list for chemistry teachers.

PHET energy skate park simulation
PHET energy skate park (

You can do more online than you ever could in real life, leading to far larger sample sizes and much more accurate data. Take advantage of this by emphasizing the data analysis and evaluation components of your virtual labs while concentrating more on the design and procedure aspects of your usual hands-on experiments.

Stick with reusable materials

I know it can be tempting to use a bunch of disposable supplies with a large class (or classes) as it makes cleanup so much easier, but with just a little extra effort you can really put a dent in your laboratory waste.

First on my list would be to replace paper towels with cloth wipes. You can purchase these, or simply make them by sewing a few layers of old towels together to make a really absorbent and tough wipe that can handle any mess your students can make. Avoid using microfiber cloths as they are made from plastic. Also, kids seem to go through a roll of paper towels like it's nothing, so don't give them the opportunity!

Another thing I would recommend is to use beakers or washable containers for experiments rather than paper or plastic cups. Yeah, you're going to have to wash them up afterward, but set the expectation that your students are going to be responsible for their own cleanup and you won't be creating any more work for yourself.

Start saving glass jars, soda bottles, milk and egg cartons, tins, and other food containers for use in your lab. I have found large plastic peanut butter jars with tight-fitting lids to be particularly useful. These repurposed materials can be especially helpful with younger students who are less careful with glass and less likely to need precision equipment for their labs.

mesocosm science experiment in peanut butter jars
Simple mesocosms set up in peanut butter jars

I always do a forces and structures unit with grade 9 that involves an engineering challenges project. Students construct bridges, towers, houses, and other buildings out of popsicle sticks, straws, paper, and whatever else we have lying around. It's good fun, but it's also very wasteful, so this year I decided to use K'Nex building sets instead. I was lucky to pick up a bunch of these from our elementary school which recently closed. Besides being reusable, the bridges my students made ended up being stronger and much more realistic than the ones made with flimsy disposable craft supplies. Awesome!

bridge building structure k'nex student project
Grade 9 bridge building with K'Nex

Go paperless

When I started teaching more than 10 years ago, I was kind of obsessed with handouts and worksheets. I filled my students' notebooks and binders with things I had created and thought I was being super organized. I knew I was making a ton of copies, but the idea of going paperless seemed impossible.

lesson plans and handouts in binders on shelf science teacher
A collection of my handouts and lesson plans which are mostly collecting dust now that I do things digitially

Fast forward a couple of years and all of my students suddenly had a device in class. At first, this was a set of student laptops or tablets, but nowadays most students prefer to use their own devices instead. This was a game-changer for me, and I started using email and Google Classroom to share all of my assignments. Even for math class, which I thought would be impossible given the nature of writing formulas and symbols, I have students who prefer to use their tablets and touchscreens to complete their work. Sure, there are some negatives associated with constantly having access to a screen, but these are manageable, and you can't argue with the environmental impact of saving dozens of reams of paper every year. Most of my students now submit their work on Google docs or as PDFs, and occasionally, as photos of their work.

Collaborate with other schools and universities

Sometimes you don't have the materials or equipment necessary to do the labs you really want to do. Sure, you could fill out a bunch of forms, beg your supervisors, and wait weeks or months for those expensive items to arrive, or you could simply work with another school that has what you need.

If everyone took advantage of collaborative resources, it would mean far less waste since not every school would need to be fully outfitted with its own supplies and equipment. There are no shortage of schools with better resources than yours, both locally and globally, and in my experience, many of their teachers would be happy to collaborate on a project with you if you give them enough planning time. This works best when you offer to work together, of course, by providing them with data or access to your own school's equipment (virtually, in many cases). Even if you don't have much to offer, you can still mention that your students would like to work with theirs, creating the opportunity for interesting and realistic collaboration to occur between teams of students.

Years ago my students in Japan were doing a biology project where they wanted to know how much energy they were using during exercise. We had a spirometer and could measure the volume of air being inhaled and exhaled, but the students had difficulty converting this into an estimation of energy utilized based on the oxygen they were consuming. We didn't have a chemistry teacher at the time, so I asked for help on a teacher's forum. A school from Vienna, Austria responded and offered to connect with my class, and the students pretty much took it from there. Were the results perfect? No, but by problem-solving and overcoming communication challenges, it was evident that the students from both schools gained a lot from this experience.

Another worthwhile idea is to contact colleges and universities. I once got a supply of pig hearts from a university lab for free just by sending a cold email and asking where I could obtain dissection supplies. I've also taken students on field trips to university labs to use their PCR equipment, microscopes, and other expensive supplies that we would otherwise never be able to afford. The costs of these experiences are cheap or even free, minus travel expenses, and many colleges are more than happy to help out in the hopes of engaging with potential future students and scientists.


While there is no way to completely avoid waste in your class, you can definitely reduce the amount without negatively impacting your students or their experiments. I hope the above tips can help you do just that.

Pin this article to save it for later:


bottom of page