This Duckweed Inquiry Lab is Fun and Engaging!
There’s a huge push to move toward more inquiry biology labs. I’m glad for that, because it’s definitely more interesting for students and teachers both.
It’s a win-win situation when you can run a biology inquiry lab that is engaging and also uses easy-to-find materials and isn’t very complicated. I like using simple living organisms when I can. Early in the school year, when we’re working on scientific method, I like to use this Duckweed Inquiry Lab.
If you’re not familiar with duckweed (Lemna minor), it’s a small, aquatic plant commonly found in ponds and lakes. It’s often seen floating on the surface of the water.
It serves as a food source for certain ducks and insects and is a good indicator of water quality. It’s a really neat little plant!
Starting the Investigation
I started this out with my students by having them do short web search to find out some information about duckweed. They learn about how it grows, what conditions it likes and why it’s useful for research.
The next step is for the teams to start planning out their experiment. I gave them a class period to get this done. Students filled out a recording sheet where they learned how to count their duckweed plants, make some observations, and brainstorm some variables they might test.
I’m always a bit surprised during this part of the lab. My students usually test pretty well on the scientific method and seem to understand it. But when it comes to actually implementing a science inquiry they get totally lost. I guess this is one of the reasons for the new NGSS!
They tend to have difficulties in coming up with suitable hypotheses … meaning ones that are measurable. They seemingly forget that they need a control, and they often want to just dump in lemon juice or salt into their poor duckweed!
So I’m typically kept pretty busy circulating and answering questions and doing check-ins with each of the teams. I collect their recording sheets at the end of class, not to grade them but to look them over to make sure they’re finally all on the right track.
Setting Up Our Duckweed Labs
The next day, we go over some last minute details and I reiterate some of the points they need to keep in mind. Then they start their set ups! It’s really enjoyable watching them work together and they seem to really have fun with this part.
I typically have them take data for 10 days. I give them about 5 minutes at the beginning of class to check their containers, take some notes and pictures and refill the water if necessary. Of course, weekends are an issue. I do tell them that if they want to come in on weekends to check, I’ll gladly come and let them in the building … so far no-one has taken me up on that!
I encourage them to take pictures with their phones each day. At the end of the inquiry lab they’ll compose a formal lab report and I like to have them use some of the pictures they’ve taken in the reports.
Speaking of the lab reports … the students collaborate on Google Drive to write their reports. I really like doing it this way because it allows me to see who did what work. I give them the option of using a Doc or Slides to complete their report and everyone in the group gets the same grade. (There are exceptions to this, of course … if someone really did nothing then I certainly wouldn’t penalize the whole group). But for the most part, they all distribute the work pretty evenly.
All in all, this is a fun lab that both the students and I enjoyed. It really gives them a taste for scientific work and it’s simple to set up. There’s good practice at the end with the lab reports, too.
If this is something you might be interested in, I do have this up in my store. Click the image below to go check it out.
If you give this a try I’d LOVE to hear how it goes for you! Do you have any other fun inquiry labs you’ve tried? We’d love to hear about them!