Healthy Soils
In this activity, participants will explore different types of soil. They will learn how human activity and climate change can affect the quality of soil. Note: the activities can be quite messy and are best done outside.
This activity is inspired by the activity “Soil-Air-Water” developed by Let’s Talk Science at Memorial University – Grenfell Campus. It was modified for a climate-focus by the Let’s Talk Science National Office in 2024.
This workshop discusses topics which can lead to feelings of eco-anxiety among volunteers, educators and youth if not presented in a thoughtful manner. The most important things to remember are to be honest, hopeful, developmentally appropriate, and action oriented. This workshop was created with these guidelines in mind. For more details, refer to the volunteer resource, Being Conscious of Eco-Anxiety
What You Need
Materials
- Recycled jars with lids (3)
- Recycled bottles with caps (3)
- Clear plastic cups or jars (4, 3 for the samples and 1 to pour water)
- Soil samples, such as:
- Sand
- Clay
- Topsoil with plant matter (such as grass with roots attached)
- Large container for water
- Shovels and buckets/bags to collect soil samples (as applicable)
- Buckets of water to wash hands and sanitizer if a sink is not accessible.
Guide:
Safety Notes
Speak with the educator to establish the boundaries of the area that the participants can explore. Refer to the Learning Through Nature Quick Reference Guide for facilitating an outdoors outreach visit.
What To Do
Pre-Activity Prep
- Cut a large opening on one side of each bottle. Avoid cutting the neck of the bottle.
- Discuss with the educator beforehand if participants will be able to collect soil samples for the activities. If not, bring samples with you. Have an alternative plan in place if the weather is poor.
Introduction
- Introduce yourself and today’s topic:
We are going to explore different soil samples and learn about what types of soil are good for plants. We will also talk about how human activity and climate change are affecting soils.
- Use the background information to ask the participants a few questions to establish their understanding. Adjust the questions based on the age of the participants. Example questions include:
- What is soil?
- How is soil formed?
- Why is soil important for plants to grow?
- Ask the educator to separate the participants into pairs or small groups.
Activity 1 – Soil Composition
This activity is to be done at the beginning of the visit, so that there is enough time for the soil to settle in layers.
Instructions
- Examine the different soil samples by moving the soil between your fingers.
- What does it feel like? Are the soil grains gritty, smooth, small or large?
- Fill the jars about 1/3 way with each soil sample.
- Add water to each jar and tightly fasten the lid.
- Shake the jars and set them aside to settle.
- After the other activities, look at the layers of each soil sample.
- Which soil sample had the most layers?
- Try to identify what is in each layer. Why do you think the layers settled that way?
Activity 2 – Soil Runoff
This activity can be done as a group demonstration depending on the materials available.
- Use the Background Information to introduce how human activity and climate change can affect the quality of soils.
Instructions
- Place the bottles on a bench or table or have someone hold the bottle horizontally.
- Fill each bottle with a soil sample. As you fill the bottles, push down on the soil to compact it gently. Make sure the bottle cap is securely fastened.
- Place the empty cups directly underneath the neck of each bottle.
- Remove the bottle caps.
- Slowly start to pour water into each bottle while keeping it horizontal. Once the soil is saturated, water should start to pour into the cups below. Add equal amounts of water to each bottle.
- Discuss some of the following:
- How much water did the soil samples absorb before it started to collect in the cups?
- What did the water runoff look like? Was the water clear, cloudy, dirty?
- Which sample do you think represents the best soil for plant growth? The worst?
- What can happen in nature, or because of climate change, to make soil become mostly sand? What about the clay soil? See the “What’s Happening” section.
Activity 3 - Scavenger Hunt
This activity is optional. Participants should not disturb things or collect items – they should aim to leave everything the way it was found.
Instructions
- Each group will try to find:
- A place where soil is being formed.
- A plant growing in an unusual place.
- A non-plant (animal/bug/worm/mushroom) living in soil.
- Something that will become soil one day (plant/leaf/rock).
- Discuss some of the following questions:
- Where was the plant growing? Why were you surprised to find a plant growing in that spot?
- What non-plant did you find? What is its role in the soil?
- Would the item you found become soil through the process of physical, biological (decomposition) or chemical weathering?
Wrap-Up
- Discuss ways that participants can lower their greenhouse gas emissions and help in the fight against climate change.
- Discuss possible careers and what participants will need (schooling, experience) to get into those careers.
Note: It is important to be conscious of your audience and consider that not all youth have the same options available to choose from (i.e. rural students may not have access to public transit, food availability and choices are not always equal). Allow youth to come up with their own ideas instead of directing them on what to do.
Discovery
To sustain plant life, soil must be able to hold onto water, air and nutrients. Soils play a key role in filtering water from pollutants, cycling nutrients, and providing support for plant roots and human structures. Soil is the foundation to healthy ecosystems and biodiversity.
In the soil runoff activity, participants should notice that the dry, sandy soil does not hold onto much water and that the water flows very fast into the cup. This causes a lot of sand to go into the cup. The sandy soil represents what happens under extreme desertification - the topsoil and clay become so dry that wind erodes it away, leaving only sand behind. This soil has a poor structure, making it easy for wind or water to erode it away.
The soil with high amounts of clay holds onto more water than the sandy soil, and water starts to pool in the bottle when saturated. This soil is very thick and sticky when wet and the runoff is very cloudy. This soil represents what happens when water or wind erosion occurs and the topsoil is removed, leaving behind a layer of soil with poor drainage that can be hard for plant roots to grow in.
The topsoil with plants absorbs a lot more water and the water flows into the cup once saturated, but not as much as the sandy soil. This soil represents healthy soil, where plants help provide structure so that the soil remains together and is porous enough to allow water drainage.
Soils are critical in maintaining sustainable ecosystems and biodiversity. Soil is also important in the production of the food we eat and many products we rely on. Soil can be damaged by human activity like deforestation and climate change. Another concern is that when soil loses the ability to retain water and support plant growth, it can cause chemicals in the soil (like pesticides and fertilizers) to erode into water sources and cause other environmental problems like algal blooms.
- After collecting the water samples from the soil runoff activity, have the participants design a filter to clean the water and make it “drinkable”. Which sample was the easiest to clean? Which was the hardest?
- Soil - Resource page from Let’s Talk Science that includes backgrounders, hands-on activities and career profiles related to soils.
What's Happening?
To sustain plant life, soil must be able to hold onto water, air and nutrients. Soils play a key role in filtering water from pollutants, cycling nutrients, and providing support for plant roots and human structures. Soil is the foundation to healthy ecosystems and biodiversity.
In the soil runoff activity, participants should notice that the dry, sandy soil does not hold onto much water and that the water flows very fast into the cup. This causes a lot of sand to go into the cup. The sandy soil represents what happens under extreme desertification - the topsoil and clay become so dry that wind erodes it away, leaving only sand behind. This soil has a poor structure, making it easy for wind or water to erode it away.
The soil with high amounts of clay holds onto more water than the sandy soil, and water starts to pool in the bottle when saturated. This soil is very thick and sticky when wet and the runoff is very cloudy. This soil represents what happens when water or wind erosion occurs and the topsoil is removed, leaving behind a layer of soil with poor drainage that can be hard for plant roots to grow in.
The topsoil with plants absorbs a lot more water and the water flows into the cup once saturated, but not as much as the sandy soil. This soil represents healthy soil, where plants help provide structure so that the soil remains together and is porous enough to allow water drainage.
Why Does it Matter?
Soils are critical in maintaining sustainable ecosystems and biodiversity. Soil is also important in the production of the food we eat and many products we rely on. Soil can be damaged by human activity like deforestation and climate change. Another concern is that when soil loses the ability to retain water and support plant growth, it can cause chemicals in the soil (like pesticides and fertilizers) to erode into water sources and cause other environmental problems like algal blooms.
Investigate Further
- After collecting the water samples from the soil runoff activity, have the participants design a filter to clean the water and make it “drinkable”. Which sample was the easiest to clean? Which was the hardest?
- Soil - Resource page from Let’s Talk Science that includes backgrounders, hands-on activities and career profiles related to soils.
