So my school is currently virtual (just for a few more weeks). We are starting our unit on cells and I wanted something to grab my students attention. We start with Life Processes; think MRS. NERG (movement, reproduction, sensitivity, nutrition, respire, and growth). It’s a pretty simple topic but students struggle to remember all seven.
This is where Sewage Lice comes in. I got the idea from Flinn Science. Here is the link to their lesson. In their lesson they tell the story of a Dr. from the University of Wisconsin sending you a sample of a new life form, Sewage Lice. Although this backstore works I decided to change it up to make it easier for my kids to buy in.
For my version I showed my students pictures of my house with its current issues (see pictures below). Although the hole in my ceiling was really caused by a leaking top toilet tank I was able to convince my students that it was really Sewage Lice. I gave them a fancy name, Pediculus spurious, which translates to false lice. I explained to my students that they have evolved from common lice due to living in the sewers and were now 100x larger than normal lice.
They are able to swim to find their food (sewage) and to reach the top of water (to breath). I explained that when they run out of sewage they can eat through pipes, like they did at my house.
By this point my kids were asking if my house is ok and if I had a picture of the lice to show them. I let them know that I can do one better, I collect specimens for us to look at together. Cue the various reactions: what!? no way!? gross!? I don’t want to see them!? YES!!!
So of course I show them and I point out to them: Do you see them swimming? What about their air bubbles as they breath underwater? See how they swim down to grab food and then swim back up for air?
The students are super intrigued by this point and that’s when I hit them with, “Do you want to see me eat one?”
After a moment for all of the reactions, I ate one which off course cues even more responses. After a little bit, I finally review the truth. Sewage lice are made up; they aren’t real. That’s what starts the discussion about why we thought they were alive. From there we can dive into what the seven processes that living things must do to be classified as biotic or living.
Want to do the experiment with your own students? All you need is carbonated soda (I used sprite) and raisins or craisins. It’s a great way to start the year, discuss living things or just look at observations.