SCIENCE DOCENT GUIDE HELPING HANDS SCIENCE 4 GOMES ELEMENTARY Fourth Grade Math Science Nucleus 2016 1
DOCENT GUIDELINES FOURTH GRADE 4 DURATION: 50-60 minutes GENERAL INFORMATION: Do not spend more than 10-15 minutes for an introduction and instructions. Allow as much time for the hands on component. If you are doing an art project, make sure you have all the materials readily available. If you are teaching a new concept to fourth graders make sure they understand some of the vocabulary. You may need to repeat large words and have students repeat the word. Leave about 5 minutes to discuss what they did in the lab and urge them to develop a summary or conclusion of what they learned. Note: Background information is added information for the docent only. Decomposition Planned Lessons Decomposers Food Chain (poem) Lesson Overview Students look at different type of decomposers that are part of the thermophilic, mesophilic and cool (mature) compost. NGSS CORRELATION 4-LS1-1. Plants contribute nutrients needed for decomposition ESS2.E: Biogeology Organisms in composting Identifying the different types of organisms in compost ESS2.E: Biogeology Soil Description Investigation of natural soil and compost. ESS2.E: Biogeology 4-LS1-1. Plants contribute nutrients needed for decomposition 2
FOURTH GRADE DECOMPOSERS lesson 1 OBJECTIVES: Learning about the food chain and decomposerss role Sorting different decomposing organisms 4 VOCABULARY: Decompose rs producers Scavengers Carnivore Omnivore MATERIALS: Food Chain by Cassy Fries worksheets BACKGROUND: The environment is full of different animals with different needs. Students should learn early how these organisms are grouped. Every organism needs to find food, whichh is the basis of the food chain (single chain) and food web (many chains). In food webs there are many layers. Theree are decomposers who make areas ready for producers to grow. Decompose rs can use their eating habits to produce heat (bacteria, actinomycetes) that further break down organic debris that helps other organisms like fungi to adsorb nutrients. There are many different food chains in a specific area. Otherr organismss are just like humans in that most vary their diets. If an organism relies solely on one organism for food, the first organism will be in trouble if the second dies out. Individual organisms, however, prefer specific food, but they usually varyy their diets depending on what is available. The food chain refers to "who eats whom" relationship. For instance, humans eat hamburger whichh comes from the meatt of a cow, which eats only grasss (herbivore). But humans don' 't only eat meat, they eat many other items that come from both animals and plants (omnivore). If you plotted the entire food habits of an organism this would be called a food web. PROCEDURE: 1. Read the poem Working on a Food Chain. 3
2. Make sure students understand the concepts of consumer, producer, and decomposer. You can go through the poem again and include some of the concepts on the right. There are many ways to refer to the components of a food web. If you wish to determine the place that an organism has in a food chain you would use the terms decomposer, producer and consumer. A decomposer would be organisms like fungi, annelids, ants and bacteria. A producer would be organisms that photosynthesize and a consumer is predator. There are be different levels when you develop a food web. 2. Hand out the picture on Decomposers in Compost. Go over the different organisms. Note that these are specific groups. Not all arthropods are found in compost, but then some like ants are a vital part. 4
Through the 4 th grade lessons, students will be learning about the different roles of the organisms found in compost. They will learn about thermophilic (heat loving), mesophilic (warm loving) and mature (cool) composting and the different organisms that you find in the compost you are creating. 3. Hand out the plastic models and see if students can identify them on the Lab Worksheet (Compost Organisms). Some they may be familiar with like beetles and worms, and others like Fungi and Actinomycetes, might be foreign to them. 4. Discuss the different organisms. 5. Hand out one tub of Life Cycle of Worms, and Life Cycle of Ants. Ants (Insect) and Worms (annelids) are very important in cool composting. These animals are some of the most important organisms that gets soil ready for plants to grow. Ants are one of the few animals that can digest wood (as students will learn later) and worms help to churn up the ground and add nutrient as they go their life cycle. LIFE CYCLE OF ANTS Eggs: After mating, a princess ant is considered a queen ant. She finds a good nesting site to start a colony, where she lays thousands of tiny eggs. She won t leave the nest until the first generation of worker ants are ready to search for food. Once her colony is established, a queen ant may lay thousands of eggs each day. Larva: Eventually, ant eggs develop into larvae, which resemble tiny pieces of rice. They have no eyes, only a mouth and they are fed by worker ants that bring food to the nesting site. It takes between a week and a month for eggs to turn into larvae, depending on the species. Pupa: A few weeks to a month after becoming larvae, the growing ants will be ready to spin cocoons, called pupae. Within a week or so, pale yellow ants will emerge. They turn their normal color once their exoskeleton hardens. A queen s first batch of ants will be smaller because they have not been fed by other worker ants within the colony. Ant: Once its exoskeleton hardens, an ant is ready to begin supporting the colony. Worker ants are by far the most common, but some ants can also develop into soldier ants, drones, or princesses. The worker ants have distinct tasks, including caring for eggs, finding food, or expanding and maintaining the colony. 5
LIFE CYCLE OF WORMS Eggs: Earthworms are hermaphroditic, meaning they have both male and female characteristics, so they can both fertilize and lay eggs. Eggs are contained in a sheath that slides of the worm after fertilization. The sheath becomes a cocoon that is deposited in the soil, where it hardened to protect the eggs inside. Hatchling: Worm hatchlings emerge from their protective cocoon at different rates depending on the species, but the range is from three weeks to five months. Temperature and moisture also impact the amount of time it takes hatchlings to emerge. Only a few hatchlings survive to exit the cocoon. Juvenile Worm: Depending on the species, it takes anywhere from 10 to 55 weeks for worms to mature. They grow daily and are mature once they have the ability to lay and fertilize eggs. Worms: There are thousands of species that are considered worms, including varieties of annelids like earthworms and red worms, and parasites like hookworms and pinworms. In nature, worms are vital to ecosystem because they act as decomposers, moving decaying material back into the soil where it can feed plants and continue the cycle of life. 6. Find some worms from outside and put a few at each table. Ideally you would need a clear container to students can look at the worms. 6
FOURTH GRADE --lesson 2 ORGANISMS IN COMPOSTING OBJECTIVES: Identifying microbes in compost. Exploring the biology of composting. 4 VOCABULARY: thermophilic actinomyetes fungi Bacteria mesophilic MATERIALS: hand lens clear plastic covers White spoons or popsicle sticks Compost from local composter Identification cards Draw an organism worksheet. BACKGROUND: Bacteria and fungi digest organic matter and convert it into different chemical forms that are used by other microbes, invertebrates and plants. During thermophilic composting the populations of various types of microorganisms will change as conditions change. The world of microbes in compost is diverse and mysterious. The energy that they release during their struggle to stay alive, creates another ecosystem that helps to further digest and change organic material. There is always a challenge in compost in that your mixture produces an end product that has carbon and nitrogen in balance. Making compost at the beginning can produce smells but once it gets an earthy smell then the compost is ready. In this lesson we will have the student explore the different microbes that they can find. It is not important what their names are, but that students look for organisms that help this complex chemical process. Below are some of the organisms the students may see. Drawing pictures can help them look at the organism careful. 7
Nematodes Nematodes, or roundworms, are an abundant invertebrates in the soil. Typicallyy less than one millimeter in length, they prey on bacteria, protozoa, fungal spores, and each other. Though there are pest forms of nematodes, most of those found in soil and compost are beneficial. Fermentation Mites Fermentation mites, also called mold mites, are transparent-bodied creatures that feed primarily on yeast in fermenting masses orr organic debris. Literally thousands of these individuals can develop into a seething mass over a fermenting surface. As a result, they often become pest species in fermenting industries, suchh as wineries and cheese factories. They are not pests in the compost pile. Springtails Springtails, or collembola, along with nematodes and mites, dominate in numbers among the soil invertebrates. They are a major factor in controlling fungi populations. They feed principally on fungi, but also on nematodes and small bits of organic detritus Redworms and Earthworms Redworms and earthworms play an important part in the break-down of organic materials and in forming finished compost. Red worms are usually 2-3 inches long and are important in warm composting debris. The more common earthworms are important in natural soil. As worms process organic materials, they coat the material with a mucus film that binds small particles together into stable aggregatess and helps to protectt nutrients from being leached out by rain. These stable aggregates s give soil a loose and well-draining structure. Ground Beetles Ground beetles have many epresentatives lurking through litter and soil spaces. Most of them feed on other organisms, but some feed onn seeds and other vegetable matter. Wolf Spiders Wolf spiders are truly "wolves" of the soil and compost communities. They don't build webs, but run freely, hunting their prey. Depending on the size of the spider, their prey can include all sizes of arthropods- invertebrate animals with jointed legs and segmented bodies. Centipedes Centipedes are frequently found in soil and in compost communities. They prey on almost any type of soil invertebrate near their size or slightly larger. 8
PROCEDURE: 1. Go over first five slides of the powerpoint on compost. Big point is that decomposition in the soil requires a lot of organisms. Decomposition can be hot (produced mostly by bacteria) which speeds up decomposition. Other decomposers are cool, like worms, which do not produce heat. 2. Provide students with main sheet and cards with the organisms used in composting. 3. Using the cards and the compost food chain sheet, ask them to put them into the different tropic levels. Are they primary consumers, secondary consumers or tertiary consumers. (they should lay them out in rows). (see gray box on next page) 4. Pass out the bins of compost. (10 bins) Have the students look for organisms in the compost. They can use the popsicle sticks to gently scoop out any organisms and put them in a clear cover so they can see them better. (you will need to emphasize the gently part, there should be no squishing or messing about with real animals). They should use their hand lens to look at the organisms. 5. Give them the draw the organism worksheet. Have them identify and draw the organism and write some info about it from the card. They should add as much detail as they can to the drawing based on what they observe (rather than what they think the organism looks like). 6. If they get done quickly, they can draw a second organism on the back (some students put in a lot of detail and take time and others are done too fast. Encourage those that are done too quickly to look again and put in more detail. If they still are done before the rest, have them draw a second organism). 7. Have them return all the animals to the dirt after drawing (or they will die). Do not put the covers on too tight for overnight (between classes is fine) so they can have air). 8. After the last class, you can dump the dirt into someplace in the school garden. 9
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Draw a Compost Organism Name: My organism is a I learned this animal (use the info on the cards to say something about your animal: Look at the animal with your hand lens. Try to draw as many details as you can. 11
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FOURTH GRADE SOIL DESCRIPTION lesson 3 OBJECTIVES: Investigating natural soil. Comparing compost with natural soil. 4 VOCABULARY: soil soil horizons topsoil MATERIALS: worksheet different soil samples trays magnets handlens BACKGROUND: Soil is composed of organic matter and broken down rocks. The organic matter is from other surrounding life that has started to mix with the small rocks. Many soil dwelling organisms spend their lives breaking down dead animals and plants, releasing nutrients for use by growing plants. These decomposers, sometimes called reducers, are responsible for the fertility of the soil. The constituents of soil are extremely variable in size, shape and chemical composition. The size of particles is one of the most significant characteristics. Water absorption, air movement, rate of solution and ease of tillage are a few things that are affected by particle size. The texture of soil refers to particle sizes and is classified on an arbitrary scale. It can be coarse, sandy, or clayey. Sand would be about the size of sand, coarse would refer to soil that is larger and clayey would be smaller. You can also describe the structure of soil by how the soil particles stick together. When particles are rather porous and small, the soil is considered to have a granular or crumby structure, which is characteristic of many soils high in organic matter. Soil that is lumpy usually sticks together. Sometimes soil has magnetite in it, a magnetic mineral that is attracted to a magnet. Humus, the partially decayed organic matter accumulated in soils, is a dark-colored structure less material. Making compost would simulate and speed up nature s way of making humus. 17
Soil horizons can be different for high productive areas versus low productive areas. The ideal soil horizon as shown in the Pre Lab, may not be present in all areas. You can use the following to help guide you with your students. PRODUCTIVE A. contains more organic matter in most areas, most weathered and leached at all levels, loose, easily tilled, fertile B. Yellow layer containing small quantities of clay and easily penetrated by air, water, and plant roots C. slightly weathered, permeable, calcareous NON PRODUCTIVE A. light gray layer, low in fertility and difficult to till B. heavy clay layer impermeable to air, water, and plant roots, massive stable aggregates of small particles C. heavy clay parent matter Nutrients in the soil are important to plants in order to survive. Nutrients can be complex organic molecules like carbohydrates, fats or protein. They can also be inorganic like zinc or copper. However all nutrients are composed of elements in a chemical state that can be used by the organisms. In a process called photosynthesis, plants use energy from the sun to change carbon dioxide (CO2 - carbon and oxygen) and water (H2O- hydrogen and oxygen) into starches and sugars. These starches and sugars are the plant's food. Photosynthesis means "making things with light". Since plants get carbon, hydrogen, and oxygen from the air and water, there is little farmers and gardeners can do to control how much of these nutrients a plant can use. The 13 mineral nutrients, which come from the soil, are dissolved in water and absorbed through a plant's roots. There are not always enough of these nutrients in the soil for a plant to grow healthy. This is why many farmers and gardeners use fertilizers to add the nutrients to the soil. The mineral nutrients are divided into two groups: macronutrients and micronutrients. Macronutrients can be broken into primary and secondary nutrients. The primary nutrients are nitrogen (N), phosphorus (P), and potassium (K). These major nutrients usually are lacking from the soil first because plants use large amounts for their growth and survival. The secondary nutrients are calcium (Ca), magnesium (Mg), and sulfur (S). There are usually enough of these nutrients in the soil so fertilization is not always needed. Also, large amounts of Calcium and Magnesium are added when lime is applied to acidic soils. Sulfur is usually found in sufficient amounts from the slow 18
decomposition of soil organic matter, an important reason for not throwing out grass clippings and leaves. Micronutrients are those elements essential for plant growth which are needed in only very small (micro) quantities. These elements are sometimes called minor elements or trace elements. The micronutrients are boron (B), copper (Cu), iron (Fe), chloride (Cl), manganese (Mn), molybdenum (Mo) and zinc (Zn). Recycling organic matter such as grass clippings and tree leaves is an excellent way of providing micronutrients (as well as macronutrients) to growing plants. Notice that all the components are ultimately composed of chemicals. However, there are inorganic components that are "given" or specific to an area. The ecosystem has to build itself on soil (organic matter + rock). Organic matter is carbon based, but rocks can be made of a variety of chemical compounds which add character to a particular soil. Remember, minerals make-up rocks, and minerals can be composed of elements or compounds. PROCEDURE: 1. A soil profile is a slice of earth several feet deep that illustrates the layers of soil. Most soil profiles have a surface layer of organic material and two or three layers of soil layers with different characteristics. Students in this lab will look at 4 samples representing ideal O, A, B, and C horizons. 2. Give students soil samples, magnet and handlens. It would be ideal to get local samples for this lab and to record where the sample came from. Only the docents will use water for demonstration. 3. Instruct the students to look at the reference soil samples under the hand lens and describe what they see. They should ask themselves if the sample has broken up rocks or very fine clay particles. They should also see if there are other distinguishing characteristics like plant debris or animal remains. 4. If you have time you may want students to go outside and dig a hole to see the soil horizon around the school. This may be difficult in some areas. Students could collect some of the samples. If not enough time is available, the teacher should pre-collect the samples. 5. Docents can put a little amount of the soil in some water to see if anything floats. Plant debris floats and rock will sink. 6. Use the magnet to see if there is any magnetite, which is a magnetic mineral. You can use the magnet with the reference collections. The presence of magnetite means that the parent rock may have been granitic. Magnetite erodes out of the rock and is left in the soil 19
PROBLEM: How can you distinguish the different soil horizons? PREDICTION: Surface: organic material dead plants, animal material O horizon Topsoil: plant roots, bacteria, fungi, small animal A horizon Subsoil: Fewer organismss less topsoil; plants don't grow well B horizon Altered Parent Material: Weathered, less living matter layers above were formed form it C horizon MATERIALS: different soils samples, magnet, microscope, hand lens, cup of water Look at the different horizons of soil and describe each below. SOIL DESCRIBE CHARACTE ERISTICS HORIZON 20
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