Teaching Sequence

15 minutes

Tune In: What's going on under the ground?

20 minutes

Find Out: Where do worms sit?

20 minutes

Take Action: Our wriggly helpers

05 minutes

Reflection

Tune In: What's going on under the ground?

Step 1

There’s a lot happening under our feet! Show students the following video:

After watching the video, run a 'See, Think, Wonder' with your students.

What did they see in this video?
What do they think was happening?
What does it make them wonder?

Step 2

Let’s watch another video that shows us what is happening under the ground:

Wow! That was pretty amazing. Ask your students: What did the worms eat in this video? Their answers may include:

leaves
paper
cardboard
ice (for moisture)
eggshells (for calcium).

Follow up with the question, what happened to the things the worms ate? Students may use phrases such as ‘broke down, munched up, went squishy, turned into dirt, got pooped out’. Encourage them to use a range of adjectives and verbs to describe the process.

Find Out: Where do worms sit?

Step 1

Share with students that there is a special word for when things get broken down, munched up, etc., and this word is ‘decompose’.

Worms are one of the animals that help decompose things, so we call them decomposers. Worms decompose things by eating them! But can worms eat everything? Create three lists with your students: one of the things worms can eat, one of the things they can’t eat, and one of the things we’re not sure about. To kick things off, you might suggest the following items:

an apple core
a sandwich
a chocolate wrapper
a watermelon
wood
rocks
a glass jar
meat
an aluminium can
animal scat.

This last one can be a bit interesting. If your class can have a giggle and move on it’s a great one to include as an important part of the food chain. If you think it will derail the activity too much, leave it out.

Step 2

Ask students what the items in each list have in common. If they are struggling to find the commonalities you can suggest the ‘living things test’:

Does/did this thing grow?
Does/did this thing breathe?
Does/did this thing reproduce?

The things worms can eat are/were living. The things worms cannot eat are non-living.

Once you have established this, re-visit the list of things you weren’t sure about. Using the living/non-living criteria, can you sort them into their correct list?

Step 3

So, we know worms intake food, decompose it by digesting it, and produce scat called worm castings. These worm castings are an important part of healthy soil.

If students have some experience with worm farms, they may know about ‘worm tea’ already. Worm tea is just water that has passed through worm castings to create a product often used as a natural fertiliser. It’s sometimes called ‘worm wee’, but worms don’t urinate. They get rid of wastewater through their skin similar to how we sweat.

Step 4

On the board draw a worm, an arrow, and some soil like this:

Ask students, what living things need soil? While they might make a few suggestions, the easiest one to proceed with is a plant. Draw another arrow and add it to your diagram. Explain that the arrow shows the energy moving from one element to the next (i.e. from the worm to the soil, soil to the plant). Now we’re starting to build up a food chain! Let’s see how far we can go.

Ask your students, what eats this plant? Choose a student’s suggestion and draw an arrow followed by what eats the plant. Ok great! Now, what eats (student’s suggestion?) Work through the food chain until either you hit a top-level predator or a student suggests the next step could be an animal which is a decomposer. Your food chain might look like this:

Step 5

But our food chain doesn’t end there. What happens when our top predator dies? They get eaten by something too! What do you think eats them? We’re looking to create a link back to our original decomposer here.

Extension: If students suggest another animal, such as a vulture or another scavenger, you can follow that line of inquiry by building it out into a food web. Does the energy go to the top and cycle around and around? If so, why don’t we have hundreds of top-of-the-food-chain animals around? Lead them to the idea that eventually, the energy will end up with our decomposers. Draw an arrow leading around to your decomposer.

Step 6

Once a decomposer has taken in the energy, where does it go? It’s already on our food chain! And now we can see how the energy flows around the system.

Learning Support: Instead of asking for ideas, you could use the above food chain elements and ask students to put them together in the correct order.

There are four different components in this system. These are:

energy (represented by the arrows)
producers (who make stuff)
consumers (who eat stuff)
decomposers (who break down stuff).

Which ones do you think are consumers? Which ones are producers? And which one is the decomposer? Label the different elements of the food chain using the above terms.

Literacy extension: Writing Prompt:

What would happen if there were no decomposers?

Ask students to write a short imaginative piece of 3 - 5 sentences.

Take Action: Our wriggly helpers

Step 1

Could we make a worm farm for our class/school? Watch the video below with your students. As you watch through the video, create a list of materials you would need to create a worm farm.

Now we have established our goal, it would be an option to divide your class into groups and assign Steps 2 - 4 to different groups so they can work on these steps at the same time.

Step 2

After watching the video, review your list of resources. Where could we get these from? Are there any alternatives that we can substitute? For example do we have an old wheelie bin we could use instead of a styrofoam box? Or old shade cloth we could use instead of fly screen?

Try and re-use or repurpose resources as much as possible. It is possible to do this project completely free! If buying worms/eggs for your worm farm isn’t an option, see if you can find someone in the community (such as a parent, or a local community garden) who would be happy to divide their worm farm and supply you with worms.

Numeracy extension: How big will your worm farm need to be? Take a sample of the amount of green waste your class produces in a day. Will your class use the worm farm, or will it be the whole year level? Or school? Worms take about 2 weeks to break down food scraps, so your bin should be large enough to hold 2 weeks worth of scraps.

Step 3

Create a timeline for building your worm farm. You’ll need to include elements such as:

sourcing materials
putting it together
making a sign for your worm farm
setting it up in the correct place
installing the worms
sharing your accomplishment with family and friends.

Plan when the different steps will happen and who will be responsible for meeting this timeline. Building your worm farm won’t happen in this lesson, so when can we do these steps?

Step 4

Now we need to establish our processes around the worm farm. To do this we need to answer a few questions.

Where will the worm farm go? It will need to be in a cool, shaded area as the worms can overheat quickly in even a little sun. Will you keep the worm farm near where students eat lunch, or will you keep it near where the products will be used? If you keep it further away, will you need a container to collect scraps from lunch and a roster for someone to put them in the worm farm?
What can go in the worm farm? This may take a little internet research! Earlier, we established that decomposers can break down anything that was living. However, to maintain a non-smelly and healthy worm farm, there are some things you should avoid putting in your worm farm. It’s a good idea to make a sign to go on your worm farm to make sure only the right things are going into it.
Who is responsible for maintaining the worm farm? It’s a good idea to check your farm once a week. You may find it is getting too wet (and needs shredded paper), or too dry (and needs a light spray with water or some ice added). If the farm gets too full, it will need to be divided into another farm. Periodically, it will need to be harvested for both worm tea and the castings. You could set up a roster for students to do the checks, you could work with your school’s environmental group or gardening group, or set up a plan with your school’s maintenance staff.

Looking to save time? Check out our Worm Farms: Getting Started Factsheet to help you on your way.

Reflection

Now we have our plan let’s reflect:

What is one challenge we might face in creating our worm farm?

How could we overcome this challenge?

Working for Scraps: Worm Farms for the Classroom

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Summary

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