Summary
Overview
Forests are the green lung of the Earth and home to millions of different plant, fungi, animal, and bacteria species. Unfortunately, today many forests are threatened by deforestation, which causes significant biodiversity loss. Ongoing reforestation efforts across the world intend to counteract the effects of deforestation. As planting trees by hand does not scale well, machines on the ground, as well as flying drones have been developed to help plant tree seedlings or seeds. In this lesson, students will be challenged to design and build their own miniature seeding machine that will place seeds on a grid in a specific pattern as quickly as possible.
Remote Learning: This lesson plan can be conducted remotely. The Engage section of the lesson can be done over a video call, then students can work individually or as a virtual group during the Explore section, using the Student Worksheet as guide. In a virtual group setting, each group member would need to build their own prototype. A set of materials can be prepared in advance or students can use materials found around the house. The Reflect sections can be done over another video call. Students can present their final design solutions either on the call or they can share pictures or drawings of their designs on a class drive.
Learning Objectives
- Explain the impacts of deforestation on climate change and biodiversity.
- Practice using the engineering design process to build a machine that fits specific design criteria and constraints.
- Evaluate competing design solutions based on the agreed-upon design criteria.
NGSS Alignment
This lesson helps students prepare for these Next Generation Science Standards Performance Expectations:- MS-LS2-5. Evaluate competing design solutions for maintaining biodiversity and ecosystem services.
- MS-ETS1-2. Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of a problem.
- MS-ESS3-5. Ask questions to clarify evidence of the factors that have caused the rise in global temperatures over the past century.
| Science & Engineering Practices | Disciplinary Core Ideas | Crosscutting Concepts | |||
| Science & Engineering Practices | Constructing Explanations and Designing Solutions.
Undertake a design project, engaging in the design cycle, to construct and/or implement a solution that meets specific design criteria and constraints.
Engaging in Argument from Evidence. Evaluate competing design solutions based on jointly developed and agreed-upon design criteria. |
Disciplinary Core Ideas | LS2.C: Ecosystem Dynamics, Functioning, and Resilience.
Ecosystems are dynamic in nature; their characteristics can vary over time. Disruptions to any physical or biological component of an ecosystem can lead to shifts in all its populations. Biodiversity describes the variety of species found in Earth's terrestrial and oceanic ecosystems. The completeness or integrity of an ecosystem's biodiversity is often used as a measure of its health. ESS3.D: Global Climate Change. Human activities, such as the release of greenhouse gases from burning fossil fuels, are major factors in the current rise in Earth's mean surface temperature (global warming). Reducing the level of climate change and reducing human vulnerability to whatever climate changes do occur depend on the understanding of climate science, engineering capabilities, and other kinds of knowledge, such as understanding of human behavior and on applying that knowledge wisely in decisions and activities. ETS1.B: Developing Possible Solutions. A solution needs to be tested, and then modified on the basis of the test results, in order to improve it. Sometimes parts of different solutions can be combined to create a solution that is better than any of its predecessors. ETS1.C: Optimizing the Design Solution. The iterative process of testing the most promising solutions and modifying what is proposed on the basis of the test results leads to greater refinement and ultimately to an optimal solution. |
Crosscutting Concepts | Stability and Change.
Small changes in one part of a system might cause large changes in another part.
Influence of Science, Engineering, and Technology on Society and the Natural World. The use of technologies and any limitations on their use are driven by individual or societal needs, desires, and values; by the findings of scientific research; and by differences in such factors as climate, natural resources, and economic conditions. Thus, technology use varies from region to region and over time. |
Materials
The following are the materials needed per student group of 4 for building the seeding machine. These materials are suggestions and can be changed as needed. You can select the quantities for each item. Make sure each group receives the same quantities of each material. In a remote learning setting, the materials for each group can also be flexible.
- For potential wheels: Round objects like bottle caps or CDs, foam board or cardboard
- For potential axles: Straws, jumbo straws, wooden skewers, paper rolled into tubes, pencils, etc.
- For the body of the machine: Plastic bottles, cardboard or tissue boxes, cardboard tubes, etc.
- Construction supplies: Tape or masking tape, scissors, glue, etc.
- Other supplies: Cardstock, string, craft sticks, pipe cleaners, different-sized disposable cups, resealable bags, rubber bands, paper clips, etc.
Material per student group of 4 for testing the seeding machine:
- Dry beans, beads, or different-colored candies as seeds (24)
- Printed Seeding Template
- Stopwatch
Background Information for Teachers
This section contains a quick review for teachers of the science and concepts covered in this lesson.Forests play a major role in Earth's ecosystem. They currently cover about 31 percent of the world's land surface. But not every area covered with trees is classified as a forest. The Food and Agriculture Organization defines a forest as "land spanning more than 0.5 hectares with trees higher than 5 meters and a canopy cover of more than 10 percent." Forests that match this definition can be found on every continent, as shown in Figure 1. Thirty-one percent of Earth's total forest area is found in Asia, followed by 21% in South America, 17% in Africa, 17% in North and Central America, 9% in Europe, and 5% in Oceania (Annual Review of Ecology, Evolution, and Systematics, 2013. 44:593-622). Depending on where the forests are located, they are classified as temperate, subtropical, tropical, or boreal forests.
Figure 1. Proportion and distribution of global forest area by climatic domain, 2020 from the Global Forest Resources Assessment, 2020. Image credit: Food and Agriculture Organization of the United Nations (FAO), CC BY-SA 3.0, via Wikimedia Commons.
The trees within a forest are essential to our existence. They produce oxygen during photosynthesis as they generate energy for themselves to grow. Most living organisms need oxygen to survive. Roughly one-third of Earth's oxygen in the atmosphere is produced by the trees in the tropical forest. This is why forests are also called the "green lung" of Earth. Another reason why trees are important is that they play a major role in climate change, as they influence the amount of carbon dioxide, a principal greenhouse gas, in our atmosphere. During photosynthesis, trees also absorb carbon dioxide, a major greenhouse gas, from Earth's atmosphere. Forests are the largest carbon sinks on Earth. Each mature tree can remove up to 48 pounds of carbon dioxide per year from the atmosphere. This means that in one year, an acre of forest can absorb twice the carbon dioxide produced by an average car's annual mileage.
Another important ecological role of forests is that they are home to 80% of the world's terrestrial biodiversity. Biodiversity is a term that describes the enormous variety and variability of life on Earth. Forest ecosystems include not only trees, but many other plant, fungi, animal, and bacteria species. Forests provide a habitat for all of these living organisms. The tropical forests—also known as the tropical rainforests—are specifically rich in biodiversity due to their hot and humid climate. More than half of the world's species of plants and animals are found in the rainforests. These include monkeys, spiders, frogs, snakes, birds, orchids, rubber trees, insects, and many more. Even today there are still new species being discovered in the depth of the rainforest.
Figure 2. Distribution of living terrestrial vertebrate species. Highest concentration of diversity is shown in red, lower concentrations are shown in blue. Image credit: Mannion, P. D. 2014. Patterns in Palaeontology: The latitudinal biodiversity gradient. Palaeontology Online, Volume 4, Article 3, 1-8., CC BY-SA 3.0, via Wikimedia Commons.
Even though forests are critical for mitigating climate change and sustaining biodiversity around the globe, their existence is severely threatened. Deforestation, the clearance of forests or trees from land—either due to human activities or natural causes such as wildfires—rapidly decreases the forest areas across the world. According to the World Wide Fund for Nature (WWF) in 2019, the tropics lost close to 30 soccer fields' worth of trees every single minute! In the last 50 years, deforestation in the Amazon caused the loss of 17% of the existing forest in the Amazon! The reasons for human-caused deforestation are manifold, but the primary reason is the conversion of forest land into agriculture land, which then allows for the creation of pulp, palm, or soy plantations and pastures. Another cause is the expansion of urban areas, which leads to the construction of new settlements, roads, and other infrastructure. Many people also depend on forests for their living as they use them for goods such as timber, food, fuel, or bioproducts, which can result in illegal and unsustainable logging practices. Only half of the currently existing forests are still primary forests, which means that they are forests of native tree species and there are no clearly visible indications of human activities. The map in Figure 3 illustrates how the worldwide forest cover has been decimated over time.
Figure 3. Worldwide loss of primary forests. Image credit: Steven Fick and Elizabeth Shilts, Canadian Geographic. (The map was created from observations of the Dutch-Finnish OMI Instrument on NASA's EOS-Aura satellite.)
The effects of deforestation are devastating. Destroying the forests means destroying the food and shelter that many animals and plants depend on. The loss of these habitats directly leads to biodiversity loss, as animal and plant species eventually become extinct. According to the 2019 global assessment report on biodiversity and ecosystem services, around 1 million animal and plant species are threatened with extinction! Losing the forests also means less carbon dioxide absorption by trees. Even worse, clearing forests by burning trees releases significant amounts of carbon dioxide and other greenhouse gases. Forest loss and damage is the cause of around 10% of global warming. Furthermore, people who rely on forests for their living are deprived of their livelihood, and without trees, soil becomes prone to erosion and flooding events, which are becoming more frequent.
Because the consequences of deforestation are so severe, the United Nation included the conservation and restoration of terrestrial ecosystems in their 17 sustainable development goals. Goal 15 specifically states as goal to end "deforestation and restore degraded forest" as "forests are vitally important for sustaining life on Earth and play a major role in the fight against climate change."
There are many strategies to achieve these goals. Some measures that can help prevent habitat loss due to deforestation are:
- Protecting the remaining primary forests by law.
- Implementing sustainable forest-management strategies.
- Creating dedicated tree farms for commercial and domestic use.
- Letting degraded forests "rewild."
- Conducting large-scale reforestation efforts.
Reforestation efforts that intend to counteract the effects of deforestation are already ongoing across the world. Many organizations have dedicated their mission to planting trees in areas where they have been lost. However, planting trees by hand does not scale well and replacing billions of cut trees manually is an impossible task. This is why companies have developed specific planting or seeding machines that place tree seedlings or seeds into the ground. Some of these companies even employ drones to shoot seedlings into the ground from the air in areas that are not easily accessible.
In this lesson, students will first learn about the importance of the world's forests and the consequences of deforestation. Next, students will discuss reforestation as a solution to maintain biodiversity and then design and build a miniature seeding machine that is able to place seeds on a grid in a specific pattern as quickly as possible.
