ingridscience

Discuss what worms need to survive (ideally through close observation of a worm)
Air: the bin has holes in the lid, and the lid will be opened frequently to allow more air in too.
Water: worms need to stay moist (as they breathe through their skin, obtaining the oxygen dissolved in the water)
Food: worms eat rotting plants which are soft enough for the worm to ingest (and turn them into rich soil)
Darkness: worms burrow down away from the light to seek cool, damp places, and to hide from predators

Assemble the bin as a class
Sit the class in a circle around the empty worm bin, and assemble the bin step by step to provide the worms with what they need to survive.
1. Worms need a moist environment - make a layer of wet newspaper in the bottom of the bin to keep the environment damp: distribute trays of water around the circle. Distribute a sheet of newspaper to each student. Ask the students to lay their newspaper sheet in the water, then crumple it into a loose ball (about 5-10cm diameter) to gently squeeze the extra water out. Pass around the worm bin for students to add their wet newspaper balls to it, to make a layer of wet newspaper balls covering the bottom of the bin.
2. Add the worms: add the red wigglers/small garden worms in a little soil. (Students can also add worms they have been looking closely at.)
3. Worms need food: students can each add a piece of old vegetable to the bin, to form a scant layer. Do not add to much as mould growth on the uneaten vegetables can take over the worm bin. Avoid sweet fruits (apple cores, banana peels, orange peels) as this attracts fruit flies.
4. Cover the soil to keep it moist: students tear newspaper into long strips, then layer this on top of the worms and their food. This keeps the moisture in and any fruit flies out. It also makes a dark space for worms to crawl around in and find food.
5. Place the lid on. Air will enter through small holes in the lid, or a tightly-sealing lid should be opened periodically to let fresh air in.

Discuss long term care of the worms
The bin should be kept out of direct sunlight and away from heaters, to keep it cool.
Food should be added when the worms have consumed the previous food. Too much food will invite mould growth.
The bin should be kept damp but not soggy: worms need to stay moist, but will drown in too much water. Any added water should be chlorine-free.
When the newspaper strips are getting broken up, mix them in and add a new layer on top.
After a month or so, the worms will have made new, rich soil from the vegetable scraps. This soil can be added to garden or potted plants as fertilizer.
Sometimes, plants will grow from the seeds added to the bin (see third photo).

See the worm bin care sheet for more detailed information (attached).
Also more information here: http://compost.css.cornell.edu/worms/moreworms.html

Dismantling the worm bin
When the worm bin is taken down, the freshly made compost/rich earth can be separated from the worms and put on plants that need fertilizing.
Look out for baby worms, and even worm eggs (about 1mm long, dark red-brown and egg shaped with one pointed tip) - see photo.
The worms can be put in a garden, or kept to make a new worm compost bin.

Setting up a second compost bin, from a previously made compost bin:
As above, make a layer of wet balls of newspaper in the bottom of the new bin. Take several handfuls of soil, rich with worms, from the old compost bin (you could use the entire bottom layer of soil and worms if this layer is not too deep). Layer over the old vegetables and dry newspaper etc, as described in the instructions above.

Before handing out the worms. practice using magnifier; look at the lines on your finger.
Look more closely at worms and how their body structure helps them survive in their habitat.

Hand out one worm per student enclosed in a small petri dish with a film of water in the bottom.
Ask students to draw what they see (not what they think they see).
After a while, ask the students what they have noticed. Ask if they noticed the segments, how they move, the blood vessel, the dark soil in the gut, which is head and tail.
Allow more time for the drawing.

Show image of worm and relate to what students have found, and which body parts are similar and different to ours.
Head, tail, mouth, anus, segments, clitellum, blood vessel. Organs: heart, brain, blood vessels.
Try this link for an image: https://thebiologynotes.com/nervous-system-of-earthworm/

How do worms breathe?
We breathe by pulling air into our lungs. Worms breathe through their skin, by absorbing the oxygen from water - hence they need to stay moist to keep getting oxygen.

How do worms see? (There is no obvious eye).
Although we can't see any eyes on a worm, they do have rudimentary eyes. Eyes closed activity to show how worms see: ask students to look up at the light, then close their eyes and notice that they can still see some brightness. While keeping their eyes closed, face away from the light and notice how the light dims. Worms are able to detect where the light is with rudimentary eyes - they cannot focus to see an image but can detect which direction the light is coming from. This allows them to dig down into the soil (away from the light) to avoid predators.

How do worms move?
They move by muscle contraction and by gripping with the bristles (called setae) on each segment.
See these images to show the sequential muscle contractions that move them along:
https://www.macmillanhighered.com/BrainHoney/Resource/6716/digital_firs…
https://www.researchgate.net/figure/Earthworm-Locomotion-Mechanism-adap…

Other worm information:
They are both male and female in the same body but still need to mate to reproduce, by joining clitella (the smooth band on their bodies near the head).
They are decomposers, eating dead plant and animal matter and turning it into soil. They also aerate soil as they dig through it, making it more habitable for plant roots and other soil animals.

States of matter in water demonstration
1. Here is an ice cube (or give each student one). Is it solid, liquid or gas? Why? Fixed size, fixed shape.
What is happening to it? Melting. It is changing to a liquid because it is getting warm in the hand. The molecules are moving apart enough that they can flow past each other and make drips of liquid.
The name for a solid changing into a liquid is Melting.
2. Now we start with liquid water. We can turn it into a gas by warming it up even more - give it more energy. Use a see-through kettle or a hot plate to boil water.
What is happening to the liquid? Bubbles of gas are forming in it. It has enough energy to heat it up enough to turn to gas. The name for a liquid turning into a gas is Evaporation. (Alternatively, spread a drop of water on black paper and in a warm classroom or in the sun you can watch it evaporate.)
3. Now we will turn the gas back into a liquid by cooling it down. Put a glass lid/bowl over steam escaping from hot water - see droplets of water forming inside the glass. Why do the drops form on the glass? Because it is cooler, and they lose enough energy to move more slowly and become water again. The name for a gas turning into a liquid is Condensation.
4. How can we make the liquid turn back into a solid?
Cool it down even further. Optional: make frost on the outside of a can: www.ingridscience.ca/node/227 (set up at the start of the lesson - it takes 15 mins to form). Name for a liquid to a solid is Freezing.

Measure the temperature of water in each state
1. Measure the temperature of ice:
Half fill a styrofoam cup with ice cubes, then immerse a thermometer in it. Read the temperature once it has stabilized (maybe a few minutes). If the thermometers are properly immersed in the ice they should read 0°C or below. Students can add their temperature reading to a graph on the board. Explain that ice forms at 0°C and remains solid at any temperature below that.
2. Measure the temperature of liquid water:
Pour water into the cups by mixing boiling and cold water to vary the warmth of the water in each cup. Ask students to measure the temperature of their water, and add it to a graph on the board. All measurements should read between 0°C (the melting point of water) and 100°C (the boiling point of water).
3. Measure the temperature of liquid water boiling:
This should be a demonstration. Using heat proof tongs, dip a thermometer into the water as it comes to the boil. Ask one student to read out the temperature as it rises to 100°C (the boiling point of water). If the thermometer can be held in while it continues to boil it may rise above 100°C, as more and more bubbles of gas form within the water.
4. Optional: graph the temperature data. Liquid water will always be between 0°C and 100°C. Ice will be at or below 0°C. The gas in boiling water can be above 100°C.

Discuss what a solid, liquid and gas are.
A solid is hard. The particles are packed together so tightly that we cannot push through it and we can see it.
A liquid we can see but the particles are further apart, so it can flow and we can move it around with our hand.
A gas we cannot see as the particles are so far apart. But we can feel the particles hitting our hand (wave hand through the air).

Students are given a clipboard holding their scavenger hunt worksheet, and a pencil.
Students hunt around the classroom or school grounds looking for solids, liquids and gases. They write down each item and check off whether it is a solid, liquid or gas. They should try and find at least one of each state.
Gather to review and discuss.

Could be used as a review for older students - ask them to look around from where they are sitting and find a solid, liquid then gas.

Prepare the activity:
Lay a piece of cling wrap over the top of the plastic tub. Use masking tape to secure the cling wrap most of the way round, leaving it open the last 1/4 of the length.
Add the salt and food colouring at one end of the plastic tub (make separate piles). Place the pot in the middle of the tub.
Alternatively, students can later add the salt as you visit each of their tables to set up the water cycle model.

In class:
Boil the water, then immediately add it on top of the salt to a depth below the rim of the pot (it will not work unless the water is only just boiled). Clip the lid shut by securing the cling wrap with binder clips. The cling wrap may balloon up. Place the marble in the middle of the cling wrap, and push the cling wrap down, so that the marble is directly over the pot.

After 5 mins or so, drips of re-condensed water will fall from under the marble into the pot. After 10 or 15 minutes there will be enough drips of water in the pot to have made a puddle.

The students can optionally taste the water in the pot ("the lake") and the tray ("ocean") - give them a Q tip to dip first in the lake water and taste, then use the other end of the Q tip to dip in the ocean and taste. The ocean water is salty and the lake water is fresh. Only the water evaporates from the ocean - the salt is left behind. The food colouring also stays in the ocean, but does not appear in the lake.

Each student makes a bracelet with coloured or shaped beads. The beads are threaded in an order that represents the stages of the water cycle.
With with smaller pony beads we repeated the cycle four times and with large shaped beads we used one of each bead shape.
Once made, an adult can secure their bracelets on each student's wrist. By tucking the pipe cleaner ends inside the adjacent beads, an unbroken circle of repeating bead colours represents the endless cycling of water on earth.

If using the worksheet and small coloured beads:
Cut a short length from each student's pipe cleaner before class.
Distribute the short lengths of pipe cleaner and one set of the 6 bead colours, to each student.
Students thread the beads on the short piece, in the agreed colour order for each water cycle word. Tape the short bead sequence on the worksheet next to the water cycle words. This key shows which colour represents each stage of the water cycle.
Then students use their longer pipe cleaner piece and more beads to make their bracelet, in the correct bead colour order, and repeating several times.
(Alternatively, coloured pencils/markers can be used to show the bead colours of each water cycle word on the worksheet).

If using the worksheet and larger wooden bead shapes:
Draw the bead shapes next to each water cycle word.
Then make the bracelet in the correct order of bead shapes.

Optional: start by reviewing the states of matter, while asking students to find examples in the classroom. Solids have a fixed shape and are hard. Liquids can change shape, but always take up the same amount of space (same volume) as they flow in their container. Gases change shape and fills the space they are in (so change volume). Some students might mention plasma, the 4th state of matter.

The particles (molecules or atoms) are arranged differently in different states of matter. Tell students that they will model the particles in each of the three states of matter. They are each a molecule. Ask them to stand in an open space of the classroom.
In a solid the molecules are packed tight, held together by strong bonds. Ask students to model a solid by linking arms with their neighbours, so that they are packed tight together in a group. The individuals can jiggle a little, but the group maintains its shape.
As a solid gains energy the molecules gain energy and can move around more. They are still bonded to each other, but more loosely. Ask students to model a liquid by spreading apart and moving around more, but always touching at least one other student with an outstretched arm. The bonds between molecules break and form continuously, so that the group stays together but can move and change shape, like a liquid.
As a liquid gains even more energy the molecules gain enough energy to move completely apart and evaporate. Ask students to break all bonds with each other and move around the room, spreading out to fill the room. Students can be asked to lose energy and become a liquid again (condensation), then a solid (freezing).

For younger students, simplify the language:
Stand up close together, arms linked. Stay still. You are not moving. You are stuck together, so you cannot change shape. I can see what shape you are. Which state are you? Solid.
You have a bit more energy. Now you can move around a little more. Walk around, but always stay touching at least one other person. So you can change shape but stay the same size. Which state are you? Liquid.
Now you have even more energy. You can now move around even more, let go of each other. You now can change shape and size. Which state are you? Gas.

Videos of educators/students acting out states of matter:
https://www.youtube.com/watch?v=FUa3F2CfbPE
https://www.youtube.com/watch?v=rmBRpuXI5AA

Image of particles in the three states: http://wps.prenhall.com/wps/media/objects/943/966267/fig10.gif
Longer cartoon video of the particles in solids, liquids, gases at https://www.youtube.com/watch?v=guoU_cuR8EE

Each student: open a small baggie and add 2 tablespoons whipping cream, 0.5 teaspoons sugar and 2 or 3 drops of vanilla essence. Seal. Double bag the mixture by fitting this bag neatly inside a second baggie. Hang the baggies down the inside of a large container (500/650 g/ml) and fold the ziplock top over to the outside of the container. The bottom of the baggies should be hanging near the bottom of the inside of the container. Two students can hang their bags on each side of the same container.
Each pair of students: add 2 tablespoons of salt and about 10 ice cubes to a the container. The container should be about 2/3 full.
Snap the lid on the container over the top of the baggie.
Holding the lid on, shake the container for 5-10 minutes (yes, it takes a while), until the cream turns solid. (Double bagging ensures that punctures of a baggie by the ice cubes do not go through both layers.)
Eat out of the baggie with a spoon - quickly before it melts again!

Ice cream is frozen cream with air pockets that make it light.
The air is added as the cream is shaken.
The temperature is reduced enough to freeze the cream by adding the salt. The salt lowers the freezing temperature of water, so that as the ice melts, liquid water lower than zero centigrade surrounds the cream, causing it to freeze.