Could worms save the world? (If they’re speedy!)

Feel like you need to add a little excitement and real world problem solving in your lessons? A simple answer: saving the Earth with worms. In this lesson students not only learn about exciting developments in biological pollution mitigation, but they also learn or review the basics of speed….and, of course, play with worms!

Even kids (or teachers) who might find worms a little squeemish will enjoy and remember this lesson. Let’s not fall into the trap of doing activities for the sake of fun activities. What are we learning today with the worms?

• TEKS 7.7.A calculate average speed using distance and time measurements from investigations
• TEKS 7.7.C measure, record, and interpret an object’s motion using distance-time graphs
• TEKS Physics 4.4.A generate and interpret graphs and charts describing different types of motion, including investigations using real-time technology

Though these standards are specific to the State of Texas, calculating and graphing speed are foundational skills for general sciences and are included in the NGSS under headings such as MS-PS3-1 “Construct and interpret graphical displays of data to describe the relationships of kinetic energy to the mass of an object and to the speed of an object” and NGSS for high school physics HS-PS2-A “Analyze data to support the claim that Newton’s second law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration.”

Here is a brief overview of the lesson using the 5E Model:

• Engage: Could worms save the Earth?
• Explore: Worm races
• Explain: Graphing worm motion
• Elaborate: Calculating speed
• Evaluate: Speed calculating practice & Exit ticket

NOTE: Graphing and calculating speed can be challenging depending on the math skills of your students. This lesson cycle might take several days if you need to include some re-teaching on the basics of graphing and division or units.

Engage: Could worms save the Earth?

Have students share their thoughts. Could these worms (or the enzymes scientists hope to replicate from their digestive system) solve our pollution problem?

Media tells us that the climate crisis is dire, so let’s figure out if these little worms could work fast enough to eat up all the plastic. Question: How fast is a superworm?

NOTE: Depending on your students’ level of engagement and math savvy here, this might be a great place to insert a type of Fermi problem to have students estimate how much plastic they think might be in the world. Given that order of magnitude of plastic, how much time would it take worms to eat it all? Same question as above.

Explore: Worm Races

Materials needed (per group) : timer/stopwatch, 2 meter sticks, tape, adding machine tape or other long, light colored strips of paper, marker or pen, superworm.

Student Instructions & Student worksheet

In this activity students will work collaboratively to measure and record the motion of a worm, the first step to calculating the worm’s speed. It can be helpful to assign roles to each team member for this activity such as:

• Track timer: starts and stops timer, calls out time intervals
• Worm wrangler: takes out worm, safely keeps worm on track
• Recorder: marks worm locations (back end of worm) on track with pen
• Materials manager: picks up and returns materials, sets up and maintains track

Use the student instructions sheet to have students set up the “track” for their racing worm. Final track will look something like this:

As explained in the student instructions, one student places the worm at the start of the track while others are prepared with the marker, timer, and recording sheet. It works best if the Timer student says “start” and then calls out “mark” at five (or 10) second increments. When the Timer says “mark” the marking student makes a mark at the back of the worm to mark the space. Repeat for 3 or 4 trials.

After each trial students write down the distance indicated by each mark on the white paper – another great reason to use meter sticks for making the track! (TIP: make sure students have their meter sticks oriented correctly with the zero mark at the “start” location for the worm.)

Once you have the data you can modify the rest of the lesson based on your objectives and your students. I had my students use the graph and questions provided on this student worksheet to first calculate average speed for the entire “race” for each trial and then graph the speed:

It is useful to facilitate a discussion about the units that are appropriate here, too. If you ask students about units for speed they usually think of miles per hour but clearly that is not appropriate for our worms! What unit did we use to measure distance (centimeters)? What unit did we use to measure time (seconds)? So if we look at our formula for speed:

We can see that speed is distance (centimeters) over time (seconds). Have students brainstorm other ideas for speed units. See how creative they can be. My personal favorite is nanometers per Magic School Bus episode.

The worksheet also introduces the concept of analyzing the shape of different graphs to determine the motion, a skill which is foundational in later physics classes. I have my higher level students follow up with this activity where they read different scenarios and then match the corresponding graph. Be careful – some graphs are distance versus time (like the worm activity) and some are speed over time!

There are several different ways to assess mastery of the concepts of average speed (total distance/total time) and speed graphs as highlighted in this lesson. I like having the students make up a story and create their own corresponding graph or write example average speed problems (with solutions) for their peers to try. You can also use this more traditional exit ticket.

You could also make this single lesson the entry event for an interdisciplinary project combining science, geometry and activism/debate. For example, if your city had a theoretical landfill with 200 square meters of plastic, how long would it take your worms to eat the whole landfill? If each worm can eat an area of about 2 milimeters for each 1 millimeter they travel, what would be the volume rate of disposal? And so on… Would worms be effective for saving the world from plastic?

You can also make the lesson more complex or higher level to align with the NGSS objective showing the relationship between kinetic energy, mass, and force or reinforcing Newton’s laws. Graphing and interpreting speed is so important as a base skill for so many topics!

You may be wondering at this point – what should I do with the worms? Several options (1) find a colleague with a classroom pet lizard or snake – yum! (2) Keep the worms in a plastic or metal box filled with cheerios or oatmeal, given them an occasional apple, and watch them breed/grow over time or (3) release them into the wild for the birds.

Hope you had speedy fun and learning!