Activities
Save the Future: A Time Mission
Play
Glossary
Bonus
Summary
Chapter 2
Chapter 1
Chapter 3
Powering the City
The Trash Trap
The Class Footprint
Bonus
These educational videos explain the production processes of paper, glass, and metals and their impact.Learn more about their recycling processes.
Bonus
Documentary about plastic recycling.
Learn all about composting and its benefits.
Bonus
Learn everything about smog.
Activities
Activities - Level 1
Activity 2
Activity 1
Activity 3
Part A:Solar rooftops Part B:The Power of choices
Part A: The Trash Trap Part B: Recycling Report
Part A:The daily journeys of the class Part B:Rethinking the journeys
Activities
Activities - Level 2
Activity 2
Activity 1
Activity 3
Part A:Solar rooftops Part B:The Power of choices
Part A: The Trash Trap Part B: Recycling Report
Part A:The daily journeys of the class Part B:Rethinking the journeys
Glossary
Infinity Symbol
The 3Rs
Recycling bins
Blackout
Glossary
Model of the city
Solar panels
Renewable sources of power
Saving power
Glossary
Smog
Carbon footprint
CO₂
Infinity Symbol (∞):
Infinity means endless. It reminds us that the future can always grow and change.
The 3Rs
The 3Rs are simple actions we can do every day:
Reduce: take fewer plastic bags when shopping.
Reuse: use your water bottle again instead of throwing it away.
Recycle: put paper, plastic, glass, and metal in the right bins.
All three steps matter. First we try to reduce, then reuse, and finally recycle what is left.
Recycling bins
Plastic binA plastic bottle can take 450 to 1000 years to decompose in landfill! Many plastics can't be recycled. That's why reducing and reusing plastic is even more important than recycling it.
Think about it: Some things can’t be recycled, but we can try to avoid or replace them. What could you do differently next time?
Glass binGlass can be recycled again and again without losing quality. Every recycled bottle saves energy, enough to power a light bulb for 4 hours!
Metal binRecycling one aluminium can saves enough energy to run a TV for 3 hours!
Compost binFood scraps and garden waste break down naturally into compost. This rich soil helps plants grow and reduces the amount of waste sent to landfills.
Blackout
A blackout means the power supply suddenly fails. It can happen when too many people use electricity at the same time.
Model of the city
City planners sometimes use scale models to test ideas before making changes in real life.
Solar panels
Solar panels capture sunlight and turn it into electricity. They work best when facing South, where the sun shines longer in Europe and in the Northern Hemisphere.
Renewable sources of power
Wind turbines They use the wind to spin their blades and create electricity.
Solar farmA large field of panels that produces more energy than rooftops alone.
Hydroelectric damA river’s flow pushes turbines, creating steady power.
Saving Power: Everyday Actions
Even small daily actions can make a big difference for our planet!
Turn off the lights when you leave a room.
Use natural light instead of lamps during the day.
Choose energy-saving appliances.
Unplug chargers and devices when not in use.
Walk, cycle, or share rides instead of always using cars.
Smog
Smog comes from two words: smoke and fog. It happens when smoke from cars, factories, or other pollution mixes with fog in the air. This creates a thick cloud over the city that makes it hard to breathe and is bad for our health.
CO₂
What is CO₂ (carbon dioxide)?CO₂ is a gas in the air. Plants need it to grow. But too much CO₂—from cars, factories, or fires—harms the climate and our health. What do CO₂ measuring stations do? They are devices that measure how much CO₂ is in the air. This helps scientists check air quality and reduce pollution.
Carbon footprint
A carbon footprint is the total amount of CO₂ and other gases produced by our daily activities, such as travelling, heating, using electricity, and shopping. It’s like measuring how much we affect the environment. The smaller our footprint, the kinder we are to the Earth.
Chapter 1
The trash trap
It was early morning in late spring, already warm, with a light breeze in the trees.Iris and Orestes were on a school field trip to the nearby mountain, walking along a wide path lined with tall pines and birdsong. The teacher led the group, reminding everyone to stay together, while most pupils chatted and enjoyed the fresh air. Orestes briefly glanced at his smartwatch. Iris: Come on, stop checking your wrist, look around!
Come on, stop checking your wrist, look around!
Look! Where does that go?
Then Iris noticed something: a narrow side trail, partly hidden by long grass and small bushes.Iris: Look! Where does that go? Orestes: Let’s check!
Let’s check!
The narrow trail curved away from the main path and led them deeper into the forest. After a few minutes, they reached a rocky slope.
At the base was the dark opening of a small cave. From above, a beam of sunlight came through a gap in the rock, lighting up something metallic on the ground. It looked heavy, old, and completely out of place in the forest.
Orestes: That’s not a rock… Iris: It’s… something else.
It’s… something else.
That’s not a rock…
It’s some kind of machine.
They stepped inside. In the middle lay a smooth metallic object, unlike anything they had seen before.On its surface glowed the infinity symbol. Three narrow key-shaped slots were carved into one side. Iris: It’s some kind of machine. Orestes: But what is it for?
But what is it for?
Go tpage
What’s happening?!
I… I think it’s starting!
Iris reached out and touched the glowing symbol.The machine trembled softly. A low hum filled the cave, and light spread across its surface until everything around them shone too brightly to see.
Orestes: What’s happening? Iris: I… I think it’s starting!
The light faded, and Iris and Orestes were back on the mountain path, but the place had changed. The air felt heavy, the sky dull. The pine forest was mostly gone, replaced by bare soil and a few trees. In the distance, unfamiliar towers rose above the city, wrapped in a thin haze. Iris: Are we back where we started? Orestes: I think so… but it doesn’t look the same. Look! There are hardly any trees.
Are we back where we started?
I think so… but it doesn’t look the same. Look! There are hardly any trees.
Three keys, three challenges. To get home, we have to find them.
As Iris and Orestes tried to make sense of what had happened, a soft beep came from Orestes’s wrist. His smartwatch lit up, displaying glowing words: The machine is broken. To return to your present, collect three keys. Each key is hidden in a challenge about the world around you. Iris: Three keys, three challenges. To get home, we have to find them. Orestes: The machine had three key-shaped slots. That’s where they go.
The machine had three key-shaped slots. That’s where they go.
The machine is broken.To return to your present, collect three keys. Each key is hidden in a challenge about the world around you.
It looks like everything just piled up here.
Determined to find their way back home, Iris and Orestes followed the path to the school.It was strangely silent, no voices, no laughter, and the playground was empty. In the schoolyard, mixed waste lay scattered everywhere, while the faded recycling bins stood forgotten in a corner. Orestes: It looks like everything just piled up here. Iris: Why would it be left like this?
Why would it be left like this?
So our school really cared about recycling.
Then why does the yard look so neglected now?
As they neared the building, Iris and Orestes peeked through dusty windows. Inside, a faded notice board held old posters, their words still readable. “Reduce, Reuse, Recycle: Our Eco Promise.”
Another poster proudly declared: “Recycling Results: Our School Saves10 Trees a Year!" Iris: So our school really cared about recycling. Orestes: Then why does the yard look so neglected now?
Reduce, Reuse, Recycle
Our Eco Promise.
10Trees
The posters, the bins, the silence… something is waiting for us.
Go tpage
The recycle bins stood quietly in the yard, as if waiting for someone to bring them back to life. The faded posters about recycling seemed to whisper a promise that had once been strong, but was now forgotten.Iris: The posters, the bins, the silence… something is waiting for us. Orestes: But where is the challenge hidden?
But where is the challenge hidden?
Activity 1
Part AThe trash trap
Team Roles
Coordinator
Recorder
Let's take a look at recycling and sorting garbage. Discuss which materials go where and why some items may go to landfill!
Keeps the team focused and makes sure everyone joins in.
Writes down the results in the table.
Presenter
Materials Keeper
Handles the Object Cards and moves them to the bins.
Shares the team’s results with the class.
Download
Activity 1
Part AThe trash trap
Team Roles
Coordinator
Recorder
Let's take a look at recycling and sorting garbage. Discuss which materials go where and why some items may go to landfill!
Keeps the team focused and makes sure everyone joins in.
Writes down the results in the table.
Presenter
Materials Keeper
Handles the Object Cards and moves them to the bins.
Shares the team’s results with the class.
Download
We did it! But… is that enough? I don’t see the key yet.
Iris: We did it! But… is that enough? I don’t see the key yet. Orestes: Maybe sorting was only the first step. The posters talked about saving trees. What if the challenge is about understanding the real impact, not just sorting things?
Maybe sorting was only the first step. The posters talked about saving trees. What if the challenge is about understanding the real impact, not just sorting things?
No numbers, only leaves...
Maybe it’s a code, showing how much was collected and how many trees were saved.
Iris leaned toward the paper bin and spotted a folded, yellowed sheet. It showed drawings of paper items, each marked with rows of green leaves. Orestes frowned: No numbers, only leaves... Iris smiled: Maybe it’s a code, showing how much was collected and how many trees were saved.
Activity 1
Part BRecycling report
Team Roles
Coordinator
Recorder
Keeps the team focused and makes sure everyone joins in.
Writes down the results in the table.
What do the leaves represent? There is more to the Recycling Report, discover the impact the school once had.
Presenter
Calculator
Explores numbers and checks the team's reasoning
Shares the team’s results with the class.
Download
Activity 1
Part BRecycling report
Team Roles
Coordinator
Recorder
Keeps the team focused and makes sure everyone joins in.
Writes down the results in the table.
What do the leaves represent? There is more to the Recycling Report, discover the impact the school once had.
Presenter
Calculator
Explores numbers and checks the team's reasoning
Shares the team’s results with the class.
Download
Look! It really adds up! If we keep recycling, we could save as many trees as the poster promised.
So this was the missing piece… the machine understands now.
The children finished their calculations.
Iris: Look! It really adds up! If we keep recycling, we could save as many trees as the poster promised. Orestes: So this was the missing piece… the machine understands now.
Suddenly, the paper bin glowed brightly. From its light, a shining key-shaped symbol rose slowly into the air. It floated for a moment, then disappeared. The first slot on the time machine was now filled.
It wasn’t just about the bins, but the choices people made.
As the green key faded, the schoolyard began to change. Green shoots and young saplings appeared. Iris: It wasn’t just about the bins, but the choices people made. Orestes: When we choose to recycle, the world responds. One key found and hope is growing.
When we choose to recycle, the world responds. One key found and hope is growing.
Chapter 2
Powering the City
The city feels bigger than before… and look at all those glowing signs. There are so many of them!
With the first key in hand, Iris and Orestes felt a surge of excitement as they headed toward the city center. Lights flickered in windows and along the streets. Iris: The city feels bigger than before… and look at all those glowing signs. There are so many of them! Orestes: It looks alive again, though there’s still a faint haze in the air.
It looks alive again, though there’s still a faint haze in the air.
Suddenly, the lights began to flicker. One by one, windows went dark, streetlights faded, and the glowing signs blinked off.
In just a few seconds, the city was plunged into silence and darkness.
Orestes looked at his smartwatch, where red letters flashed: BLACKOUT
Go tpage
System overload: BLACKOUT
It means they were using more energy than the system could handle.
Orestes: It means they were using more energy than the system could handle. Iris looked around, worried. Iris: So if the city can’t keep its lights on… how will we ever find the next key?
So if the city can’t keep its lights on… how will we ever find the next key?
Wait… do you see that? Something’s still shining.
Just as the silence grew heavier, Iris noticed a faint glow in the distance. Between two tall buildings, a narrow alley flickered with warm light. Orestes: Wait… do you see that? Something’s still shining. Iris: Let’s go, maybe it’s a clue!
Let’s go, maybe it’s a clue!
Should we go in?
They followed the glow into the alley and stopped in front of a small door.
It was a door ajar, and warm light spilled through the crack.
Iris: Someone must be inside… Orestes: Should we go in?
Someone must be inside…
This doesn’t look abandoned… someone has been working here.
They peeked through the door ajar.
Inside, they saw a small workshop filled with scattered tools, sheets of paper, and models of rooftops with tiny solar panels.
Orestes: This doesn’t look abandoned… someone has been working here. Iris: Maybe this is where we’ll find the next clue.
Maybe this is where we’ll find the next clue.
Go tpage
What are you doing in my workshop?
Iris and Orestes stepped inside, studying the scattered notes and small solar models. Suddenly, the door creaked open. A young researcher entered. Startled, they jumped back. Researcher: What are you doing in my workshop?
We’re looking for keys to fix a machine and save the future.
We saw the light… we thought it might be a clue.
For a moment, no one spoke. Iris and Orestes exchanged a nervous glance. Iris: We saw the light… we thought it might be a clue. Orestes: We’re looking for keys to fix a machine and save the future. Researcher: Keys? Future? You’d better explain.
Keys? Future? You’d better explain.
I’m Nelly. Your story sounds strange… but I believe you.
Slowly, the tension faded as they explained the time machine, the broken future, and their search. The young woman listened, puzzled. Researcher: I’m Nelly. Your story sounds strange… but I believe you. Iris: What’s happening to this city?
What’s happening to this city?
Nelly: This city once had endless energy, but it was wasted. Producing more power isn’t enough. Without saving energy, nothing lasts. Too many lights, too much demand, and empty rooftops. I’ve tried different rooftops, but it never works. The city is divided into neighbourhoods, if each finds a solution, the lights might return. Orestes: Maybe we could try to help?
What if we put a panel here? It looks sunny…
But won’t the shadow from the tower next to it cover it in the afternoon?
Go tpage
Iris leaned over the model of the city, pointing at a tall building.
Iris: What if we put a panel here? It looks sunny… Orestes shook his head: But won’t the shadow from the tower next to it cover it in the afternoon?
Nelly: The city is made of many neighborhoods. Each one must find light again. If we explore the rooftops in different parts of the city, we can see how much energy the whole city can gain. Orestes: What do you think? Which rooftops would work best? Will you help us?
Activity 2
Part ASolar rooftops
Team Roles
Planner
Engineer
Build your city board, and experiment on how the city can gain power again with solar power!
Studies the map and makes sure everyone joins in.
Writes down the results in the table.
Reporter
Calculator
Calculates the kWh for the roofs and the neighborhood.
Presents the team’s strategy with the class.
Download
Activity 2
Part ASolar rooftops
Team Roles
Planner
Engineer
Build your city board, and experiment on how the city can gain power again with solar power!
Studies the map and makes sure everyone joins in.
Writes down the results in the table.
Reporter
Calculator
Calculates the kWh for the roofs and the neighborhood.
Presents the team’s strategy with the class.
Download
After testing the rooftops, tiny lights flickered on the model. A few buildings lit up, but most streets stayed dark. Iris: It worked, but only partly. Solar panels alone can’t power the whole city. What else can we try? Orestes: A real city needs more than rooftops. Without other energy sources, it won’t be stable. We’ll need every kind of renewable energy to make it shine again.
Go tpage
Nelly opened a drawer and spread out more models on the table: tall wind turbines, a winding river with a dam, and areas of open land where solar farms could grow.
Nelly: A city needs many kinds of power. Wind, water, sunlight… each one can bring back a different part of the light. Iris: We’ve brought life to the rooftops. Now, what could power the rest? Orestes: Let’s find out together.
Activity 2
Part BThe Power of Choices
Team Roles
Planner
Engineer
Studies the map and makes sure everyone joins in.
Writes down the results in the table.
There are still parts of the city without power! Let's think about other renewable energy to bring the lights back to the city.
Reporter
Calculator
Calculates the kWh for the roofs and the neighborhood.
Presents the team’s strategy with the class.
Download
Activity 2
Part BThe Power of Choices
Team Roles
Planner
Engineer
Studies the map and makes sure everyone joins in.
Writes down the results in the table.
There are still parts of the city without power! Let's think about other renewable energy to bring the lights back to the city.
Reporter
Calculator
Calculates the kWh for the roofs and the neighborhood.
Presents the team’s strategy with the class.
Download
It’s working. The city is alive again!
The city lit up as the final fragment joined the others, forming a glowing key that rose into the sky. Iris: It’s working. The city is alive again! Orestes: The key is complete. That’s two keys! We’re closer to fixing the machine and the future. From now on, people would also have to save energy every day.
The key is complete. That’s two keys! We’re closer to fixing the machine and the future.
Go tpage
Chapter 3
The Class Footprint
After falling asleep in the workshop, the children woke at dawn and stepped outside. The city was quiet, but the sky looked pale and the air felt heavy. The hope of the night before had faded. Iris: The sky isn’t blue anymore… it looks different.
The sky isn’t blue anymore… it looks different.
And unless we reduce it, the city will never breathe clean again?
Nelly explained that it was not morning mist, but smog—smoke and gases from cars and chimneys caused by burning dirty fuels. As they walked, heavy air and smoke filled the street. She pointed to a small station measuring CO₂ levels—far higher than normal. Orestes: And unless we reduce it, the city will never breathe clean again?
Go tpage
Go tpage
A sharp beep broke the silence. Orestes’ smartwatch flashed red, warning that CO₂ levels were critical and the air system unstable. Nelly explained that to help the city, they first had to understand where pollution came from and how everyday choices added up. Iris: So if we understand what causes the pollution, we can start to change it? Orestes: Then even small daily actions can make a real difference.
Nelly: Think of your classmates. Every day they go to school and then back home again. Each one has a different way of travelling: walking, cycling, by car or bus. Each of those daily journeys leaves a carbon footprint in the air. Iris: Yes… I remember them. Orestes: Maybe if we write them down, we can see how big that footprint really is.
Go tpage
Iris opened the notebook.
Iris: Lucas lives only 0.5 km in a straight line from the school, and yet his father drives him by car every day. Emma lives 5 km away and comes by bus. And Alex, just 1 km away, comes with his bike. Orestes: Each of us had a different way to get to school. If every trip leaves a trace, imagine what that means for the air we all share. Will you help us find out the footprint of our class?
Activity 3
Part AThe Daily Journeys of the Class
Team Roles
Transport Controller
Coordinator
Keeps the team focused and makes sure everyone joins in.
Distributes the cards and fills the tables.
How do you get to school and back home again? Let's calculate the CO₂ footprint of the class.
Reporter
Calculator
Calculates the CO2footprint from transportation.
Presents the team’s results with the class.
Download
Activity 3
Part AThe Daily Journeys of the Class
Team Roles
Transport Controller
Coordinator
Keeps the team focused and makes sure everyone joins in.
Distributes the cards and fills the tables.
How do you get to school and back home again? Let's calculate the CO₂ footprint of the class.
Reporter
Calculator
Calculates the CO2footprint from transportation.
Presents the team’s results with the class.
Download
Iris compared how classmates traveled to school—by car, bus, or bike. When Nelly calculated the results, the class’s carbon footprint appeared on the screen, bigger than expected for just one day. Iris: Our footprint is much bigger than we thought. Orestes: And that’s only for one day. Imagine a whole year. Nelly: Some trips can’t change, but others might—if we find new ideas.
Orestes: Let’s see which journeys could change, and how we can make the footprint smaller. Nelly: If we find new ways to travel, maybe the air — and the city — can breathe again. Could you help us?
Activity 3
Part BRethinking the Journeys
Transport Controller
Coordinator
Keeps the team focused and makes sure everyone joins in.
Distributes the cards and fills the tables.
How can we reduce the footprint? Which journeys can change to produce fewer emissions?
Reporter
Calculator
Calculates the CO2footprint from transportation.
Presents the team’s results with the class.
Download
Activity 3
Part BRethinking the Journeys
Transport Controller
Coordinator
Keeps the team focused and makes sure everyone joins in.
Distributes the cards and fills the tables.
Now lets compare the footprints and find the percentages.
Reporter
Calculator
Calculates the CO2footprint from transportation.
Presents the team’s results with the class.
Download
Nelly: Well done. You reduced the footprint, but transport is only one part of a city’s carbon impact. Iris: So for clean air, we must think about energy, food, waste, and everything else too? Orestes: The third key is glowing! Every small choice adds up.
Maybe. But it felt real, and that future is still possible.
Was it a dream?
Light flashed, then silence. Iris opened her eyes on the grass where the trip had begun. Orestes looked around, stunned. Orestes: Was it a dream? Iris: Maybe. But it felt real, and that future is still possible. They returned to school changed. They had learned that real change starts with our daily choices, beginning today.
Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Education and Culture Executive Agency (EACEA). Neither the European Union nor EACEA can be held responsible for them.
Enigmathico - Ecology Box - EN
Baptiste
Created on December 15, 2025
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Transcript
Activities
Save the Future: A Time Mission
Play
Glossary
Bonus
Summary
Chapter 2
Chapter 1
Chapter 3
Powering the City
The Trash Trap
The Class Footprint
Bonus
These educational videos explain the production processes of paper, glass, and metals and their impact.Learn more about their recycling processes.
Bonus
Documentary about plastic recycling.
Learn all about composting and its benefits.
Bonus
Learn everything about smog.
Activities
Activities - Level 1
Activity 2
Activity 1
Activity 3
Part A:Solar rooftops Part B:The Power of choices
Part A: The Trash Trap Part B: Recycling Report
Part A:The daily journeys of the class Part B:Rethinking the journeys
Activities
Activities - Level 2
Activity 2
Activity 1
Activity 3
Part A:Solar rooftops Part B:The Power of choices
Part A: The Trash Trap Part B: Recycling Report
Part A:The daily journeys of the class Part B:Rethinking the journeys
Glossary
Infinity Symbol
The 3Rs
Recycling bins
Blackout
Glossary
Model of the city
Solar panels
Renewable sources of power
Saving power
Glossary
Smog
Carbon footprint
CO₂
Infinity Symbol (∞):
Infinity means endless. It reminds us that the future can always grow and change.
The 3Rs
The 3Rs are simple actions we can do every day:
Reduce: take fewer plastic bags when shopping. Reuse: use your water bottle again instead of throwing it away. Recycle: put paper, plastic, glass, and metal in the right bins. All three steps matter. First we try to reduce, then reuse, and finally recycle what is left.
Recycling bins
Plastic binA plastic bottle can take 450 to 1000 years to decompose in landfill! Many plastics can't be recycled. That's why reducing and reusing plastic is even more important than recycling it.
Think about it: Some things can’t be recycled, but we can try to avoid or replace them. What could you do differently next time?
Glass binGlass can be recycled again and again without losing quality. Every recycled bottle saves energy, enough to power a light bulb for 4 hours!
Metal binRecycling one aluminium can saves enough energy to run a TV for 3 hours!
Compost binFood scraps and garden waste break down naturally into compost. This rich soil helps plants grow and reduces the amount of waste sent to landfills.
Blackout
A blackout means the power supply suddenly fails. It can happen when too many people use electricity at the same time.
Model of the city
City planners sometimes use scale models to test ideas before making changes in real life.
Solar panels
Solar panels capture sunlight and turn it into electricity. They work best when facing South, where the sun shines longer in Europe and in the Northern Hemisphere.
Renewable sources of power
Wind turbines They use the wind to spin their blades and create electricity.
Solar farmA large field of panels that produces more energy than rooftops alone.
Hydroelectric damA river’s flow pushes turbines, creating steady power.
Saving Power: Everyday Actions
Even small daily actions can make a big difference for our planet!
Turn off the lights when you leave a room.
Use natural light instead of lamps during the day.
Choose energy-saving appliances.
Unplug chargers and devices when not in use.
Walk, cycle, or share rides instead of always using cars.
Smog
Smog comes from two words: smoke and fog. It happens when smoke from cars, factories, or other pollution mixes with fog in the air. This creates a thick cloud over the city that makes it hard to breathe and is bad for our health.
CO₂
What is CO₂ (carbon dioxide)?CO₂ is a gas in the air. Plants need it to grow. But too much CO₂—from cars, factories, or fires—harms the climate and our health. What do CO₂ measuring stations do? They are devices that measure how much CO₂ is in the air. This helps scientists check air quality and reduce pollution.
Carbon footprint
A carbon footprint is the total amount of CO₂ and other gases produced by our daily activities, such as travelling, heating, using electricity, and shopping. It’s like measuring how much we affect the environment. The smaller our footprint, the kinder we are to the Earth.
Chapter 1
The trash trap
It was early morning in late spring, already warm, with a light breeze in the trees.Iris and Orestes were on a school field trip to the nearby mountain, walking along a wide path lined with tall pines and birdsong. The teacher led the group, reminding everyone to stay together, while most pupils chatted and enjoyed the fresh air. Orestes briefly glanced at his smartwatch. Iris: Come on, stop checking your wrist, look around!
Come on, stop checking your wrist, look around!
Look! Where does that go?
Then Iris noticed something: a narrow side trail, partly hidden by long grass and small bushes.Iris: Look! Where does that go? Orestes: Let’s check!
Let’s check!
The narrow trail curved away from the main path and led them deeper into the forest. After a few minutes, they reached a rocky slope. At the base was the dark opening of a small cave. From above, a beam of sunlight came through a gap in the rock, lighting up something metallic on the ground. It looked heavy, old, and completely out of place in the forest. Orestes: That’s not a rock… Iris: It’s… something else.
It’s… something else.
That’s not a rock…
It’s some kind of machine.
They stepped inside. In the middle lay a smooth metallic object, unlike anything they had seen before.On its surface glowed the infinity symbol. Three narrow key-shaped slots were carved into one side. Iris: It’s some kind of machine. Orestes: But what is it for?
But what is it for?
Go tpage
What’s happening?!
I… I think it’s starting!
Iris reached out and touched the glowing symbol.The machine trembled softly. A low hum filled the cave, and light spread across its surface until everything around them shone too brightly to see. Orestes: What’s happening? Iris: I… I think it’s starting!
The light faded, and Iris and Orestes were back on the mountain path, but the place had changed. The air felt heavy, the sky dull. The pine forest was mostly gone, replaced by bare soil and a few trees. In the distance, unfamiliar towers rose above the city, wrapped in a thin haze. Iris: Are we back where we started? Orestes: I think so… but it doesn’t look the same. Look! There are hardly any trees.
Are we back where we started?
I think so… but it doesn’t look the same. Look! There are hardly any trees.
Three keys, three challenges. To get home, we have to find them.
As Iris and Orestes tried to make sense of what had happened, a soft beep came from Orestes’s wrist. His smartwatch lit up, displaying glowing words: The machine is broken. To return to your present, collect three keys. Each key is hidden in a challenge about the world around you. Iris: Three keys, three challenges. To get home, we have to find them. Orestes: The machine had three key-shaped slots. That’s where they go.
The machine had three key-shaped slots. That’s where they go.
The machine is broken.To return to your present, collect three keys. Each key is hidden in a challenge about the world around you.
It looks like everything just piled up here.
Determined to find their way back home, Iris and Orestes followed the path to the school.It was strangely silent, no voices, no laughter, and the playground was empty. In the schoolyard, mixed waste lay scattered everywhere, while the faded recycling bins stood forgotten in a corner. Orestes: It looks like everything just piled up here. Iris: Why would it be left like this?
Why would it be left like this?
So our school really cared about recycling.
Then why does the yard look so neglected now?
As they neared the building, Iris and Orestes peeked through dusty windows. Inside, a faded notice board held old posters, their words still readable. “Reduce, Reuse, Recycle: Our Eco Promise.” Another poster proudly declared: “Recycling Results: Our School Saves10 Trees a Year!" Iris: So our school really cared about recycling. Orestes: Then why does the yard look so neglected now?
Reduce, Reuse, Recycle
Our Eco Promise.
10Trees
The posters, the bins, the silence… something is waiting for us.
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The recycle bins stood quietly in the yard, as if waiting for someone to bring them back to life. The faded posters about recycling seemed to whisper a promise that had once been strong, but was now forgotten.Iris: The posters, the bins, the silence… something is waiting for us. Orestes: But where is the challenge hidden?
But where is the challenge hidden?
Activity 1
Part AThe trash trap
Team Roles
Coordinator
Recorder
Let's take a look at recycling and sorting garbage. Discuss which materials go where and why some items may go to landfill!
Keeps the team focused and makes sure everyone joins in.
Writes down the results in the table.
Presenter
Materials Keeper
Handles the Object Cards and moves them to the bins.
Shares the team’s results with the class.
Download
Activity 1
Part AThe trash trap
Team Roles
Coordinator
Recorder
Let's take a look at recycling and sorting garbage. Discuss which materials go where and why some items may go to landfill!
Keeps the team focused and makes sure everyone joins in.
Writes down the results in the table.
Presenter
Materials Keeper
Handles the Object Cards and moves them to the bins.
Shares the team’s results with the class.
Download
We did it! But… is that enough? I don’t see the key yet.
Iris: We did it! But… is that enough? I don’t see the key yet. Orestes: Maybe sorting was only the first step. The posters talked about saving trees. What if the challenge is about understanding the real impact, not just sorting things?
Maybe sorting was only the first step. The posters talked about saving trees. What if the challenge is about understanding the real impact, not just sorting things?
No numbers, only leaves...
Maybe it’s a code, showing how much was collected and how many trees were saved.
Iris leaned toward the paper bin and spotted a folded, yellowed sheet. It showed drawings of paper items, each marked with rows of green leaves. Orestes frowned: No numbers, only leaves... Iris smiled: Maybe it’s a code, showing how much was collected and how many trees were saved.
Activity 1
Part BRecycling report
Team Roles
Coordinator
Recorder
Keeps the team focused and makes sure everyone joins in.
Writes down the results in the table.
What do the leaves represent? There is more to the Recycling Report, discover the impact the school once had.
Presenter
Calculator
Explores numbers and checks the team's reasoning
Shares the team’s results with the class.
Download
Activity 1
Part BRecycling report
Team Roles
Coordinator
Recorder
Keeps the team focused and makes sure everyone joins in.
Writes down the results in the table.
What do the leaves represent? There is more to the Recycling Report, discover the impact the school once had.
Presenter
Calculator
Explores numbers and checks the team's reasoning
Shares the team’s results with the class.
Download
Look! It really adds up! If we keep recycling, we could save as many trees as the poster promised.
So this was the missing piece… the machine understands now.
The children finished their calculations. Iris: Look! It really adds up! If we keep recycling, we could save as many trees as the poster promised. Orestes: So this was the missing piece… the machine understands now.
Suddenly, the paper bin glowed brightly. From its light, a shining key-shaped symbol rose slowly into the air. It floated for a moment, then disappeared. The first slot on the time machine was now filled.
It wasn’t just about the bins, but the choices people made.
As the green key faded, the schoolyard began to change. Green shoots and young saplings appeared. Iris: It wasn’t just about the bins, but the choices people made. Orestes: When we choose to recycle, the world responds. One key found and hope is growing.
When we choose to recycle, the world responds. One key found and hope is growing.
Chapter 2
Powering the City
The city feels bigger than before… and look at all those glowing signs. There are so many of them!
With the first key in hand, Iris and Orestes felt a surge of excitement as they headed toward the city center. Lights flickered in windows and along the streets. Iris: The city feels bigger than before… and look at all those glowing signs. There are so many of them! Orestes: It looks alive again, though there’s still a faint haze in the air.
It looks alive again, though there’s still a faint haze in the air.
Suddenly, the lights began to flicker. One by one, windows went dark, streetlights faded, and the glowing signs blinked off. In just a few seconds, the city was plunged into silence and darkness. Orestes looked at his smartwatch, where red letters flashed: BLACKOUT
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System overload: BLACKOUT
It means they were using more energy than the system could handle.
Orestes: It means they were using more energy than the system could handle. Iris looked around, worried. Iris: So if the city can’t keep its lights on… how will we ever find the next key?
So if the city can’t keep its lights on… how will we ever find the next key?
Wait… do you see that? Something’s still shining.
Just as the silence grew heavier, Iris noticed a faint glow in the distance. Between two tall buildings, a narrow alley flickered with warm light. Orestes: Wait… do you see that? Something’s still shining. Iris: Let’s go, maybe it’s a clue!
Let’s go, maybe it’s a clue!
Should we go in?
They followed the glow into the alley and stopped in front of a small door. It was a door ajar, and warm light spilled through the crack. Iris: Someone must be inside… Orestes: Should we go in?
Someone must be inside…
This doesn’t look abandoned… someone has been working here.
They peeked through the door ajar. Inside, they saw a small workshop filled with scattered tools, sheets of paper, and models of rooftops with tiny solar panels. Orestes: This doesn’t look abandoned… someone has been working here. Iris: Maybe this is where we’ll find the next clue.
Maybe this is where we’ll find the next clue.
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What are you doing in my workshop?
Iris and Orestes stepped inside, studying the scattered notes and small solar models. Suddenly, the door creaked open. A young researcher entered. Startled, they jumped back. Researcher: What are you doing in my workshop?
We’re looking for keys to fix a machine and save the future.
We saw the light… we thought it might be a clue.
For a moment, no one spoke. Iris and Orestes exchanged a nervous glance. Iris: We saw the light… we thought it might be a clue. Orestes: We’re looking for keys to fix a machine and save the future. Researcher: Keys? Future? You’d better explain.
Keys? Future? You’d better explain.
I’m Nelly. Your story sounds strange… but I believe you.
Slowly, the tension faded as they explained the time machine, the broken future, and their search. The young woman listened, puzzled. Researcher: I’m Nelly. Your story sounds strange… but I believe you. Iris: What’s happening to this city?
What’s happening to this city?
Nelly: This city once had endless energy, but it was wasted. Producing more power isn’t enough. Without saving energy, nothing lasts. Too many lights, too much demand, and empty rooftops. I’ve tried different rooftops, but it never works. The city is divided into neighbourhoods, if each finds a solution, the lights might return. Orestes: Maybe we could try to help?
What if we put a panel here? It looks sunny…
But won’t the shadow from the tower next to it cover it in the afternoon?
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Iris leaned over the model of the city, pointing at a tall building. Iris: What if we put a panel here? It looks sunny… Orestes shook his head: But won’t the shadow from the tower next to it cover it in the afternoon?
Nelly: The city is made of many neighborhoods. Each one must find light again. If we explore the rooftops in different parts of the city, we can see how much energy the whole city can gain. Orestes: What do you think? Which rooftops would work best? Will you help us?
Activity 2
Part ASolar rooftops
Team Roles
Planner
Engineer
Build your city board, and experiment on how the city can gain power again with solar power!
Studies the map and makes sure everyone joins in.
Writes down the results in the table.
Reporter
Calculator
Calculates the kWh for the roofs and the neighborhood.
Presents the team’s strategy with the class.
Download
Activity 2
Part ASolar rooftops
Team Roles
Planner
Engineer
Build your city board, and experiment on how the city can gain power again with solar power!
Studies the map and makes sure everyone joins in.
Writes down the results in the table.
Reporter
Calculator
Calculates the kWh for the roofs and the neighborhood.
Presents the team’s strategy with the class.
Download
After testing the rooftops, tiny lights flickered on the model. A few buildings lit up, but most streets stayed dark. Iris: It worked, but only partly. Solar panels alone can’t power the whole city. What else can we try? Orestes: A real city needs more than rooftops. Without other energy sources, it won’t be stable. We’ll need every kind of renewable energy to make it shine again.
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Nelly opened a drawer and spread out more models on the table: tall wind turbines, a winding river with a dam, and areas of open land where solar farms could grow. Nelly: A city needs many kinds of power. Wind, water, sunlight… each one can bring back a different part of the light. Iris: We’ve brought life to the rooftops. Now, what could power the rest? Orestes: Let’s find out together.
Activity 2
Part BThe Power of Choices
Team Roles
Planner
Engineer
Studies the map and makes sure everyone joins in.
Writes down the results in the table.
There are still parts of the city without power! Let's think about other renewable energy to bring the lights back to the city.
Reporter
Calculator
Calculates the kWh for the roofs and the neighborhood.
Presents the team’s strategy with the class.
Download
Activity 2
Part BThe Power of Choices
Team Roles
Planner
Engineer
Studies the map and makes sure everyone joins in.
Writes down the results in the table.
There are still parts of the city without power! Let's think about other renewable energy to bring the lights back to the city.
Reporter
Calculator
Calculates the kWh for the roofs and the neighborhood.
Presents the team’s strategy with the class.
Download
It’s working. The city is alive again!
The city lit up as the final fragment joined the others, forming a glowing key that rose into the sky. Iris: It’s working. The city is alive again! Orestes: The key is complete. That’s two keys! We’re closer to fixing the machine and the future. From now on, people would also have to save energy every day.
The key is complete. That’s two keys! We’re closer to fixing the machine and the future.
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Chapter 3
The Class Footprint
After falling asleep in the workshop, the children woke at dawn and stepped outside. The city was quiet, but the sky looked pale and the air felt heavy. The hope of the night before had faded. Iris: The sky isn’t blue anymore… it looks different.
The sky isn’t blue anymore… it looks different.
And unless we reduce it, the city will never breathe clean again?
Nelly explained that it was not morning mist, but smog—smoke and gases from cars and chimneys caused by burning dirty fuels. As they walked, heavy air and smoke filled the street. She pointed to a small station measuring CO₂ levels—far higher than normal. Orestes: And unless we reduce it, the city will never breathe clean again?
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A sharp beep broke the silence. Orestes’ smartwatch flashed red, warning that CO₂ levels were critical and the air system unstable. Nelly explained that to help the city, they first had to understand where pollution came from and how everyday choices added up. Iris: So if we understand what causes the pollution, we can start to change it? Orestes: Then even small daily actions can make a real difference.
Nelly: Think of your classmates. Every day they go to school and then back home again. Each one has a different way of travelling: walking, cycling, by car or bus. Each of those daily journeys leaves a carbon footprint in the air. Iris: Yes… I remember them. Orestes: Maybe if we write them down, we can see how big that footprint really is.
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Iris opened the notebook. Iris: Lucas lives only 0.5 km in a straight line from the school, and yet his father drives him by car every day. Emma lives 5 km away and comes by bus. And Alex, just 1 km away, comes with his bike. Orestes: Each of us had a different way to get to school. If every trip leaves a trace, imagine what that means for the air we all share. Will you help us find out the footprint of our class?
Activity 3
Part AThe Daily Journeys of the Class
Team Roles
Transport Controller
Coordinator
Keeps the team focused and makes sure everyone joins in.
Distributes the cards and fills the tables.
How do you get to school and back home again? Let's calculate the CO₂ footprint of the class.
Reporter
Calculator
Calculates the CO2footprint from transportation.
Presents the team’s results with the class.
Download
Activity 3
Part AThe Daily Journeys of the Class
Team Roles
Transport Controller
Coordinator
Keeps the team focused and makes sure everyone joins in.
Distributes the cards and fills the tables.
How do you get to school and back home again? Let's calculate the CO₂ footprint of the class.
Reporter
Calculator
Calculates the CO2footprint from transportation.
Presents the team’s results with the class.
Download
Iris compared how classmates traveled to school—by car, bus, or bike. When Nelly calculated the results, the class’s carbon footprint appeared on the screen, bigger than expected for just one day. Iris: Our footprint is much bigger than we thought. Orestes: And that’s only for one day. Imagine a whole year. Nelly: Some trips can’t change, but others might—if we find new ideas.
Orestes: Let’s see which journeys could change, and how we can make the footprint smaller. Nelly: If we find new ways to travel, maybe the air — and the city — can breathe again. Could you help us?
Activity 3
Part BRethinking the Journeys
Transport Controller
Coordinator
Keeps the team focused and makes sure everyone joins in.
Distributes the cards and fills the tables.
How can we reduce the footprint? Which journeys can change to produce fewer emissions?
Reporter
Calculator
Calculates the CO2footprint from transportation.
Presents the team’s results with the class.
Download
Activity 3
Part BRethinking the Journeys
Transport Controller
Coordinator
Keeps the team focused and makes sure everyone joins in.
Distributes the cards and fills the tables.
Now lets compare the footprints and find the percentages.
Reporter
Calculator
Calculates the CO2footprint from transportation.
Presents the team’s results with the class.
Download
Nelly: Well done. You reduced the footprint, but transport is only one part of a city’s carbon impact. Iris: So for clean air, we must think about energy, food, waste, and everything else too? Orestes: The third key is glowing! Every small choice adds up.
Maybe. But it felt real, and that future is still possible.
Was it a dream?
Light flashed, then silence. Iris opened her eyes on the grass where the trip had begun. Orestes looked around, stunned. Orestes: Was it a dream? Iris: Maybe. But it felt real, and that future is still possible. They returned to school changed. They had learned that real change starts with our daily choices, beginning today.
Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Education and Culture Executive Agency (EACEA). Neither the European Union nor EACEA can be held responsible for them.