Field Trips
- Grade Level:
- Upper Elementary: Third Grade through Fifth Grade
- Subject:
- Science
- State Standards:
- Cycling of Matter in Ecosystems
Standard 5.3.1 Construct an explanation
Standard 5.3.2 Obtain, evaluate, and communicate information
Standard 5.3.3 Develop and use a model
Students explore how matter moves through the Earth’s ecosystems, by focusing on carbon. In the classroom, they role play how carbon moves through Earth’s systems. On the field trip, they simulate food chains and photosynthesis. They examine decomposers and test the properties of soil crusts.
Essential Question: How does matter cycle through a desert ecosystem?
Utah State Science Core Curriculum Topic: Cycling of matter in ecosystems
Matter cycles within ecosystems and can be traced from organism to organism. Plants use energy from the Sun to change air and water into matter needed for growth. Animals and decomposers consume matter for their life functions, continuing the cycling of matter.
Standard 5.3.1 Construct an explanation that plants use air, water, and energy from sunlight to produce plant matter needed for growth.
Standard 5.3.2 Obtain, evaluate, and communicate information that animals obtain matter and energy from the food they eat for body repair, growth, and motion and to maintain body warmth. Emphasize that the energy used by animals was once energy from the Sun.
Standard 5.3.3 Develop and use a model to describe the movement of matter among plants, animals, decomposers, and the environment. Emphasize that matter cycles between the air and soil and among plants, animals, and microbes as these organisms live and die.
Background
Everything on Earth is made of matter. Matter takes up space and has mass (weight). In the desert, matter includes trees, cows, decomposers, crust, air, and water. Another surprising thing made of matter is lightning. Plasma is another state of matter in addition to solids, liquids, and gasses (note: students learn about plasma in 5th grade). Antimatter is matter composed of the antiparticles of the corresponding particles of “ordinary” matter (from Wikipedia). (Note: if students bring this up, tell them for this field trip we focus on changes in matter happening in the desert and here on earth.) Non-matter things include light and electricity. Light is photons and is a form of energy. Electricity involves the movement of electrons.
Photosynthesis is a process used by plants and other organisms where energy from the sun is used to convert carbon dioxide and water into the sugars plants need for growth. The word photosynthesis can be broken down to help understand it: "photo" meaning light and "synthesis" meaning to put together or combine. Plants obtain 95% of their mass from carbon dioxide in the air. Oxygen is also used by the plant, as plants breathe too; however, more oxygen is produced during photosynthesis than can be used, so excess oxygen molecules must be released. Stomata are pores on the leaves which, when open, allow air molecules to pass into and out of the leaf. Water enters leaves via the roots and stem of a plant. The chemical formula for photosynthesis is useful to know when trying to figure out why excess oxygen is produced 6CO2 + 6H2O (+ sunlight) -> C6H12O6 + 6O2.
Chemical bonds form in molecules when atoms share electrons. In photosynthesis, sunlight provides enough energy to break these chemical bonds so the atoms can reform into sugar molecules.
Most plants, most algae, and cyanobacteria perform photosynthesis. In contrast to our model of photosynthesis, real photosynthesis takes less than 2 seconds. Photosynthetic life converts 100-115 million tons of carbon into biomass each year. Many scientists say photosynthesis is the most important chemical reaction on earth. Not only is everything we eat (except for things like salt) basically processed sunshine, but without photosynthesis, the earth would only have life in a few deep-sea hydrothermal vents and hot springs. Photosynthesis makes complex life like humans and dinosaurs possible.
A food chain represents the transfer of matter (and energy) from the sun to living organisms. Producers are green plants that use the sun's energy directly in their photosynthetic process. Primary consumers (herbivores) feed directly on the producers. Secondary consumers (carnivores) feed on the primary consumers or other secondary consumers. Omnivores can be primary or secondary consumers.
Decomposition is the breaking down of dead organisms into smaller and simpler parts. Decomposers, such as bacteria, fungi, and invertebrates (organisms without backbones, such as: roly pollies, termites, and worms), feed on the organic material found in once-living producers and consumers. A teaspoon of productive soil generally contains between 100 million and 1 billion bacteria. Decomposers break down organic material into carbon dioxide and water, as well as nutrients. Nutrients like nitrogen and phosphorous in soils are essential for producers. The CO2 released during decomposition can then be used by plants during photosynthesis. Thus, the matter in once-living consumers (and producers) is recycled back into new producers. Scavengers are not always decomposers. Waste from scavengers often requires another step of decomposition before it can be reused.
In every ecosystem, various food chains are interconnected in a food web. Food chains and food webs represent the eating patterns of the members of an ecosystem. Each part of the food web is necessary for the health of the ecosystem. Complex interactions in a food web will be taught in middle school.
Probably, the most fragile component of this arid region is cryptobiotic soil crust. The crust is a community of microorganisms, including cyanobacteria and a variable mix of lichens, fungi, and mosses. This network of organisms plays a vital role in erosion control, nitrogen fixing, and moisture absorption. One footprint can destroy years or even decades of this community’s growth, and new growth often has a different mix of organisms than the previous crust. Because cyanobacteria use photosynthesis to grow, soil crusts are one way carbon is removed from the atmosphere and placed into the soil in the desert.
Carbon is an essential element for life and can be found in organisms, air, rocks, and water, both living and non-living parts of the planet. Carbon’s movement from one thing to the other is known as the carbon cycle. These processes happen on different time scales. Photosynthesis moving carbon from air to plants happens relatively quickly while organic matter becoming buried in sediment and becoming rock takes much longer. A finite amount of carbon exists on Earth, which typically is found in combination with other elements to form substances like carbon dioxide, sugar, and methane. Each year, the world produces more than 100 million tons of sugar through photosynthesis.
Life is based on carbon. Carbon is the fourth most abundant element in the universe by mass and the second most abundant in our bodies (after oxygen). It is known as the common element of all life. The electrons of a carbon atom can bond in many ways, which creates various allotropes, or versions, of carbon. These allotropes can have very different physical properties. Diamonds and graphite are two examples of allotropes of carbon. Carbon can also combine with other elements (create compounds) more than any other element.
Electromagnetic energy from the sun fuels almost all the planet’s ecosystems. Green plants “fix” incoming solar energy; meaning they package it with matter through the process of photosynthesis into chemical energy contained within carbohydrates. The energy in those compounds’ chemical bonds then nourishes other organisms that consume plants or plant-eating creatures, including invertebrates, fungi, and microbes that decompose dead organic matter. Students will learn more about energy in sixth grade, while fifth grade focuses on matter.
Matter Moves
(adapted from Carbon cycle role play California academy of sciences)
Objectives:
Students will be able to:
a. Explain how carbon flows between Earth systems
b. Understand there is a finite amount of carbon on earth
Essential Question: How does matter cycle on earth?
Materials: Dice (one for each student); worksheet (one per student); signs for each station; tape; dry erase marker; photos of molecules containing carbon.
Procedure:
1) Review a simple definition of matter with students (has mass and takes up space). Review that matter is neither created nor destroyed, only changed and cycled. (5 minutes)
2) Explain that a deer is an animal found in the desert. Ask students if deer are made of matter. Deer grow large, which means they contain a lot of matter. Discuss where deer get all their matter. Next, explain that the largest living things in the desert are cottonwood trees. Trees start out as small seeds and grow to be thousands of pounds. A building block of matter is an atom, and atoms can combine and rearrange to make up different molecules. Carbon is one type of atom that is found in living things on earth. It can be found in carbon dioxide, sugars, diamonds, coal, and much more (show photos as you talk about the different things). (5 minutes)
3) Tell students they will take a journey as one atom of carbon. Introduce the stations (i.e. atmosphere, land plants, land animals, water, etc.) and discuss how these are the places matter is found. Explain their carbon travel worksheets. Tell students at each station they will roll the dice. They will read what happens to them, and then record their journey by drawing an arrow showing where they traveled on their worksheet. Students should keep going until you call time. (10-15min)
4) In pairs or small groups, have students compare their journeys and look for similarities and differences. Encourage students to provide explanations for the processes underlying each of the arrows. Review the idea that carbon cycles through the system and changes form by chemical reactions, but no new carbon is ever made on Earth. (5-7 min)
5) Tell students that we will be diving even deeper into our exploration of matter on the field trip. Tell students where they are going on their field trip and discuss what to bring. (3 min)
Chain, Chain, Chain
Objectives:
Students will be able to:
a: Name the parts of a food chain
b: Understand how matter is recycled through a food chain back into the air and soil
Essential Question: What happens to carbon as it moves through the food chain?
Materials: Food chain flip book; dice and container to roll it; food chain model rules sheet; Predator/ Prey cheat sheet; carbon disks; envelopes for air and soil.
Procedure:
1) Discuss concepts students learned in other stations. Ask students to think back to the pre-trip where they discussed how matter moves through plants and animals. If trees get their mass from the carbon dioxide in the air, where do people get their mass? Discuss the concept of a food chain. Ask students to look around the area for living things or signs of living things connected to each other through a food chain. (5- 7 min)
2) Use the food chain flip book to review the parts of the food chain, include a discussion about the abundance of each level of the food chain students have observed so far on their field trip. Discuss if students observe more producers than other parts of the food chain. Next, discuss if more herbivores than carnivores live in an area and why. If necessary, distinguish between energy and matter. Plants package them both together. While the energy is used up, decomposers matter is recycled. (5 min)
3) To discover what happens to matter in a food chain, specifically the carbon, make a human model of a food chain. Assign each student to be a part of the food chain, and give them a simple hand signal they could do to signify their part. Producers wave their hands around like leaves blowing in the wind. Herbivores make deer antlers. Carnivores hold their hands up like cat claws. Decomposers hold hands together straight up and wiggle like a worm (this role is great for a teacher or parent). Have students stand or sit in a circle, intermixing the various food chain stages. Give each student three discs of carbon and place three in the atmosphere envelope. Count how many discs are in the model at the beginning and ask students to remember the number. (1-2 min)
4) The producers should start by each rolling the dice and taking a carbon disc from the atmosphere envelope. Next, have herbivores, carnivores, and decomposers roll and distribute their carbon according to the rolls and the corresponding instructions on the rules sheet. If a student loses all their carbon, they die. However they can be reborn and continue to play in the next rounds. After a few rounds, include branches falling off plants as a possible roll. When this happens, move directly to the decomposer. Play three or four rounds. (5-7 min)
5) When finished, remind students how many disks they started with in their model. Remove and count the disks in the envelope. Discuss how this model was the same or different from the real world. Use the matter diagram to review carbon’s journey through the system. Discuss the important role producers play. Reiterate matter isn’t created or destroyed, it’s just recycled. (5-7 min)
6) Share an observation of seeing lots of producers and some herbivores but few carnivores. Invite students to discuss with their neighbor if more herbivores than carnivores exist and why. Encourage students to share their thoughts with the group. (2-3 min)
7) Play a game to show the importance of having more herbivores than carnivores. Draw three parallel lines, about fifteen feet apart, across a sandy, open area. Have the group stand facing each other at the center line (close enough so students can touch outstretched fingers). The other two lines indicate safe zones. Assign a specific carnivore/omnivore to one team and a creature it eats to the other. Instruct students to think quickly, and run to their safe zone if they are herbivores or run to try and tag the prey if they are carnivores. Any tagged herbivores must join the carnivore team, and a new round begins. After a few rounds, when the teams are unbalanced, discuss viability if each side were herbivores or carnivores. Play a few more rounds until the teams are balanced and discuss again.
8) Review why students noticed lots of producers and not so many other parts of the food chain.
Decomposition
(Adapted from beetle’s Decomposition Mission Student Activity)
Objectives: Students will be able to:
a. Describe how decomposers make matter available to living plants.
b. Look for at least three decomposer organisms (and find evidence of them).
c. Discuss how organisms use matter to build their bodies and identify matter wastes produced by organisms.
Essential Question: What are decomposers and how do they move matter through an ecosystem?
Materials: pictures of decomposers; box of nutrient-rich soil with different types of decomposers; 6 trowels; whiteboard with dry erase marker; bug boxes (one per student in the class); physical and chemical changes posters; six pie tins.
Procedure:
1) As you walk to the site, point out living things or signs of living things. Once students are at the station, discuss what happens to the bodies of living things (like trees or cows) when they die. (1-2 min)
2) Give each student a pie tin with five leaves in various stages of decomposition. Challenge students to put the leaves in order from recently dead to more completely decomposed. When they are finished, invite students to share the criteria they used to order their leaves and compare displays. As a group, discuss characteristics students used to classify stages of decomposition (color, number of holes, texture changes, etc). Allow students to use their senses to explore patterns, and encourage students to explain their thinking. Explain how decomposition includes the breaking down of things into smaller and simpler pieces. Discuss the time this process takes and whether different materials will decompose at different rates. Ask students how once-living things can turn into simpler materials through digestion. (5 min)
3) Have students pick up four juniper berries and examine them. Discuss patterns similar to the leaves. Explore the area to observe other evidence of decomposition in the canyon. Find examples such as rotting leaves, cow dung, and cow bones. Discuss evidence students observe. Ask students what living things might break down big once-living things into smaller and simpler pieces. (4-5 min)
4) Encourage students to name their favorite decomposers. Introduce the FBI (fungi, bacteria and invertebrates). Define invertebrates. Show pictures of decomposers. Discuss where each might be found and the evidence each leaves behind (like spots on leaves, holes, scat or frass, etc).
5) Bring out the box of soil with decomposers in it. Invite students to share what they notice about this soil and the things they find inside, such as once-living matter and decomposers. Remind students not to touch soil with their hands since some decomposers could sting. Use trowels to observe the decomposers present in the soil. Allow each student to collect one organism and place it in a bug box to observe. Allow students to share their previous experiences with organisms they find and encourage students to use their senses to notice other characteristics of the soil. (10 min)
6) Allow students to make observations about the decomposer in their bug box. Draw one of these decomposers on the whiteboard and write “Food”, “Grow”, “Do”, and “Waste” around the organism (see image below). As a group, brainstorm and record things the decomposer in their box is doing such as crawling, breathing, thinking. Under “Food,” list possible once-living things their decomposer might eat. Under “Grow,” list body parts built from matter (like eyes, antennae, legs, brain, etc.). Finally, list waste the decomposer produces. This should include poop/scat/frass (insect poop), but be sure to focus on carbon dioxide, which may not be as obvious. (5 min)
7) For a final wrap-up, ask students what would happen if there were suddenly no decomposers.Invite students to imagine how many leaves, sticks, and logs there would be if all the plant matter in the canyon stayed for thousands of years. Discuss how decomposers consume all parts of the food chain and return matter into the atmosphere (and soil). (2-3 min)
Bio Crusts
(Adapted from beetle’s Decomposition Mission Student Activity)
Objectives: Students will be able to:
a. Describe one thing soil crust does to help plants.
b. Describe one thing soil crust does to help people.
Essential Question: Why is biological soil crust important to our ecosystem?
Materials: 6 microscopes; microphotographs of cyanobacterial sheaths; 6 pipettes; whiteboard and markers; hand lenses; water and water bottles; black paper; plastic cups; spoons; soil crust flip book.
Note: Prior to the field trip collect blocks of crypto for examination from sites slated for development.
Procedure:
1) Have students examine a chunk of soil crust under the microscope. Discuss what they notice about the crust and what they wonder about it. If students did not mention the strings, encourage them to look again and discuss. Remind students we learned about crusts in second grade and they are often called crypto. Review information students already know about soil crusts. Show microscope pictures of bio crust and describe how soil crusts grow. Discuss what makes the desert difficult for the survival of living things (it’s dry, not a lot of nutrients in the soil, wind, flash floods, heat, etc.) and, why bio crusts are important in the desert. (5 min)
2) Take students to the wash and examine the sand. Next, take students to a patch of ground with variable crust sizes and ages and discuss what they notice. Ask students to compare and contrast these areas with the sand in the wash. Point to an area where the bio crust is absent or has been disturbed (i/e and old trail) and compare. (5-7 min)
3) Tell students they are going to act like agents of the desert. Give each student a spoon, two cups, and a chunk of crust. They should first place their crust on black cardboard, blow on it, and observe how much sediment moves. Repeat the test with a spoonful of soil from the wash nearby. Next, place both samples in cups. Squeeze a pipette of water on each one and observe how the water behaves. Encourage students to suck the water back out of each sample to show how much the bio crust absorbed. (10 min).
4) When students finish, compare their results. Discuss what happened to the bio crust compared to the sand in the wind. Which sample absorbed more water. Encourage students to present evidence for which sample helps the living things in the desert, more than the other. (5-7 min)
5) Use the bio crust flip book to show why soil crusts are important to humans as well as plants. Conclude by asking students to share how they would explain soil crusts to visiting relatives. (5 min)
I am Photosynthesis
Objectives: Students will be able to:
a. Describe how photosynthesis works.
Essential Questions: What are the inputs and outputs of photosynthesis? Where do plants get the molecules they need to make sugars?
Materials: Four relay sets {1 large egg carton (sugar); 6 CO2 carton pieces; 6 H2O carton pieces; 6 O2 carton pieces; 36 ping pong balls (6 C, 12 H, 18 O)}; 10 trays; speaker and music; “Stomata” sign; “Stem” sign; roles and rules poster; stomata photo; pictures of CO2, H20, and glucose molecules.
Set up: The plant cell should contain four trays, each containing an empty sugar frame and empty O2 frames. In opposite directions, 20-30 feet away should be trays with water molecules in frames, and CO2 molecules in frames. Label these areas Stomata and Stem.
Procedure:
1) Ask students how trees get their mass. Tell them plants obtain 95% of their mass from carbon dioxide in the air. Ask students what plants need to conduct photosynthesis (sunshine, carbon dioxide, and water). Discuss how plants get these things? Remind students the air is made of tiny bits of matter called molecules. Have students think back to their fall trip to the Island in the Sky and the water molecule models they made from marshmallows and toothpicks. Show pictures of H2O, CO2, and O2 molecules. Show students magnified pictures of stomata and invite students to guess what the picture shows. Discuss the stomata, along with how water and CO2 gets into leaves. (5 min)
2) Tell students they are going to create a model of photosynthesis. Take them to the “leaf” area and show them the trays representing cells. Explain that since the goal of photosynthesis is to build sugar molecules, their goal is to build their own sugar molecule (fill up their egg carton) by collecting CO2, H2O, and sunlight. The letters in the frame stand for C= carbon, H= hydrogen, and O= oxygen. Students should count how many carbon atoms are in a sugar, which determines how many CO2 molecules are needed. Repeat with H2O. Point out the location of the stomata (opening in the area) and stem (water source). Show students the picture of a glucose molecule, and explain the egg crates help us visualize the model. (2-3 min)
3) Build a sugar molecule as a group. Have each student gather one water molecule from the soil, and one CO2 molecule from outside the “stomata,” and place the atoms in the sugar frame. They should stack extra frames on the trays next to their sugar molecules. Discuss the plant is left with a lot of toxic waste (oxygen atoms). Demonstrate what happens to leftover atoms and show students how to release O2 molecules into the air through the stomata. (4-5 min)
4) Pair students to race building sugar molecules. Give each pair a tray with an empty sugar frame and O2 frames. Go over the rules for the race. Since only one student can leave the leaf at a time, and only fetch one molecule at a time, give teams a moment to strategize. Warn them about collisions. Explain that photosynthesis only takes place when the sun shines. For this race, music will represent the sun is shining on our leaf when students can work. When the music is off, students must freeze (like freeze dance.) In addition, remind students atoms cannot be wasted. When molecules are taken apart, all atoms must form sugar or oxygen molecules. For example, you can’t take the hydrogen out of the water frame and leave the oxygens. Without the hydrogen, it’s not a water molecule anymore. Congratulate groups as they finish.
5) Have students race to reset the station for the next group. Review what plants need to make sugar, and where these molecules reach the inside of leaves. Discuss how our model is the same or different from real photosynthesis. Include the time this process takes, and what plants and animals do with the sugar and oxygen produced. (5min)
6) Discuss how limiting one or more of the ingredients of photosynthesis could affect the process. For example, little water can be found in the desert. Relate this to what happens when we forget to water our house plants. Or in the winter when sunlight is less strong, many plants choose to drop their leaves and sleep. Review why we need photosynthesis.
List of potential songs to play:
You Are My Sunshine - MANY great artists have versions of this song Here Comes the Sun - The Beatles
Walkin' in the Sunshine - Roger Miller
I Can See Clearly Now - Johnny Nash
Keep on the Sunny Side - The Carter Family or The Whites
Sunshine on my Shoulders - John Denver
Island in the Sun - Weezer
The Sunny Side of the Street - Frank Sinatra
Country Sunshine - Dottie West
Walking on Sunshine - Katrina and the Waves
Sunshine, Lollipops, and Rainbows - Lesley Gore
Steal My Sunshine - Len
Pocketful of Sunshine - Natasha Bedingfield
Sunshine Song - Jason Mraz
Soak up the Sun - Sheryl Crow
Sunrise - Norah Jones
Sunlight - Hozier
Carbon Stories
Objectives: Students will be able to:
a. Provide an example of how carbon flows between Earth systems
b. Understand a finite amount of carbon exists on Earth
Essential Question: How does carbon move around Earth’s systems?
Materials: Blank Matter diagram; story packets (4 fill-in-the-blank stories); short sample fill-in-the-blank story.
Procedure:
1) Project the carbon journey diagram from the pre-trip on the board using the document camera. Ask students to recall concepts from the field trip and fill in the diagram. Review vocabulary words and put them on the diagram. (5-7 min)
2) Remind students that carbon is never created or destroyed. Instead, it cycles around Earth’s systems, leaving and joining different compounds. Offer the idea that each atom in students and in their surroundings has cycled through organisms and Earth’s systems throughout history. (Their breakfast might contain an atom that was once in dinosaurs). They are going to write a story about these many carbon journeys. Review how fill-in-the-blank stories work by filling the short example story as a class and reading it aloud. Remind students they can refer to the vocabulary on the diagram. (3-5 min)
3) Pair students and give each group a story packet with four stories. Students should take turns providing words for the stories and reading the stories out loud to each other. Encourage students to illustrate one of the events in their carbon story or draw a cartoon panel about a part of their story when finished. (10-15 min)
4) Allow students to share funny events from their stories and or share their illustrations. As students share, point out the part of the matter diagram their event discusses. Review the idea that carbon cycles through the system and changes form by chemical reactions, but no new carbon is ever made. (5 min)
California academy of sciences. (2021) Teacher and Youth Education. Carbon cycle role play https://www.calacademy.org/educators/lesson-plans/carbon-cycle-role-play
Matre, S. V. (1979). Sunship Earth. Martinsville, IN: American Camping Association.
BEETLES Modelling Matter and Energy CyclingBeetles Project Matter and Energy Diagram - Beetles Project Beetles Project Matter and Energy Diagram - Beetles Project http://beetlesproject.org/resources/for-field-instructors/matter-and-energy-diagrams/
BEETLES Food, Build, Do, Waste http://beetlesproject.org/resources/for-field-instructors/food-build-waste/
BEETLES Decomposition Missionhttp://beetlesproject.org/resources/for-field-instructors/decomposition-mission/
Modeling Photosynthesis (CA Academy of Science) https://www.calacademy.org/educators/lesson-plans/modelling-photosynthesis-and-cellular-respiration
Addressing Misconceptions about Photosynthesis for Educators (from the Smithsonian) https://youtu.be/PL9CRhRsy5A
Science Moab Podcast- How carbon moves through the desert ecosystem https://sciencemoab.org/carbon/?fbclid=IwAR0BWEX0KWxOKzKFpdrMxGfEyK1BASALqSAC9n5v0kxCudz4Rn7nPFtuYeo
Last updated: August 2, 2022