Decay of Biomass
Subject: Science
Grade: Sixth
Time Required: approximately 90 minutes
(over several days)
Benchmarks/TEKS:
Content Skills:
• 6.11.j) Explain and illustrate the interactions between matter and energy in the
water cycle and in the decay of biomass such as in a compost bin. (TEKS 6.8.B)
Process Skills:
• 6.SP.1) Demonstrate safe and ethical practice in school, field, and home. (* TEKS
5.1.A)
• 6.SP.2) Use and dispose of materials wisely, conserve and recycle materials and
resources when possible. (TEKS 5.1.B)
• 6.SP.5) Collect data by observing and measuring. (* TEKS 5.2.B)
• 6.SP.6) Gather, analyze and interpret information using selected equipment and
tools to extend the senses, including graduated cylinders, beakers, calculators,
microscopes, cameras, sound recorders, computers, hand lenses, metric rulers,
thermometers, compasses, balances, hot plates, meter sticks, timing devices,
magnets, collection nets, safety goggles. (*TEKS 6.4.A / ≈Biology & IPC 2.B)/
• 6.SP.7) Record data through graphic works including simple graphs, tables, maps,
charts.* (TEKS 5.2.E)
• 6.SP.9) Classify, analyze, and interpret direct and indirect evidence to make and
justify decisions and construct reasonable explanations. (*TEKS 6.2.C / ≈Biology
& IPC 2.C)
• 6.SP.10) Communicate problems, propose solutions, ask well-defined questions
record results, and conclusions in student’s own words. (*TEKS 6.2.D / ≈Biology
& IPC 2.D)
• 6.SP.11) Communicate problems, propose solutions, ask well-defined questions,
record results, and conclusions in student’s own words. (* TEKS 5.2.D)
• 6.SP.14) Students will use scientific words and phrases to describe the natural
world. (A.B.M.T)
Educational Objective:
The students will observe the decay of biomass and make note of the
interactions between matter and energy.
Prentice Hall Connections:
Chapter 8, page 286
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Prior Knowledge – Student:
Students should be familiar with the concepts of matter and energy.
Prior Knowledge – Teacher:
Biomass
The natural environment contains living things. It also contains the remains of living things
that have died. The combined living and formerly-living material in a habitat is the habitat’s
biomass.
Living things store energy chemically. After organisms die, the energy remains stored in the
chemicals of which they are composed. In the environment are bacteria and other
decomposers that break down the material in the biomass. Large molecules are broken down
into smaller molecules. As matter is broken down energy is released in the form of heat.
Compost Heap
For this investigation it is recommended that the teacher create compost heap. One compost
heap can serve an entire school. Only if a full sized outdoor compost heap is impossible
should the teacher use the alternate method of creating a decomposition column in a two-liter
bottle. The decomposition column will consist merely of a two liter bottle with the top cut off
filled with organic matter.
What is a compost heap?: A compost heap is simply what the name implies. It is a pile of
compost, organic matter such as leaves and grass clippings, allowed to decay naturally.
Compost bins are sold commercially or simple enclosures can be built cheaply according to
many designs but no structure is really necessary.
More information is available at the following websites.
http://www.compostguide.com/
http://www.hgtv.com/hgtv/gl_soil_water_mulch/article/0,1785,HGTV_3634_1380840,00.html
http://digital.net/%7Egandalf/woodcb.htm
What to put in the compost heap: Compost heap ingredients can include leaves, grass and
plant clippings, newspapers, kitchen scraps, and soil.
Time frame: Mold and other evidence of decomposition may appear within the first few days
after creating your compost heap.
In two or three months soft organic material such as leaves, fruits, vegetables and grain
products will decompose dramatically.
Moisture: It is important to keep the compost heap moist in order to observe more rapid
decomposition. Avoid adding too much water to the heap or it will become waterlogged. This
can create an anaerobic environment. An anaerobic environment is one that completely lacks
oxygen. It is this kind of environment that will create nasty odors.
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Odor: Odor is a by-product of decomposition. Odors may be strong at first, but will probably
mellow after some time. The strongest odors come from animal products such as meat and
dairy products. Grapefruit rinds and grass cuttings can also produce strong odors. If you use
food scraps, mix in leaves, twigs and dried grass to reduce odors. Putting a layer of soil on top
of contents also lessens the odor.
Vocabulary:
Biomass (biomasa) – the total mass of living and formerly-living
material within a given area
Decay (decaer) – to break down into component parts, to rot
Decomposition (decomposición) – the breakdown of organic matter
from larger to smaller molecules
Organic (orgánico) – of, or related to, or derived from living organisms
For ideas on teaching vocabulary see District Strategies:
Automaticity, Word Walls, or Word Wall Extension documents in
the General Resources section of the CD.
NOTE: Above are words that students should be able to use and their
definitions. These definitions are not appropriate for students to copy
and memorize.
More Information:
For additional information see the Life Science module on the CD Rom.
Materials:
[ I = per individual student, L = per lab group, C = per classroom, T = for teacher use ]
o
o
o
o
o
o
Compost Heap (C) – created by teacher or students a month or two
prior to this study
Organic matter (L) – see Advanced Preparation
Soil (L) – recommended, about a handful
Science Journal (I) - every student should have a journal where
their science work can be collected
Thermometer* (L)
Two liter bottle (L) – with the top cut off
See District Strategies: Using Manipulatives document in the
General Resources section of the CD.
*This is a state mandated tool.
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Advanced Preparation:
The teacher will gather materials. Enough organic matter should be
gathered to fill one two-liter bottle for each lab group. Students can be
encouraged to bring materials from home.
Compost heap ingredients can include leaves, grass and plant clippings,
newspapers, kitchen scraps, and soil.
The teacher will need to make a decision about how two-liter bottles will
be used. There are basically two ways that lab groups can use the bottles.
Method 1 (Recommended): The teacher and/or students create a compost
heap outside of the classroom but with easy access. On the first day of
the investigation some organic material is made available to students.
Lab groups fill two-liter bottles with organic matter and use them for
observation. At the end of each class period the two-liter bottles can be
taken outside and emptied into the compost heap.
Method 2: If the creation of a compost heap is impossible then the twoliter bottles filled with organic matter can become smaller versions of the
compost heap and kept in the classroom. This method is not
recommended, however, since the climate-controlled conditions inside
most classrooms are not conducive to rapid decomposition.
Bottles are prepared by cutting off the top and poking several small holes
in the sides of the bottle. Holes can be made with a thumb tack or a
diaper pin.
Procedures:
1. The teacher will engage the students by asking them what happens to
living creatures after they die. From here the teacher will lead a
guided discussion in which the following points are made.
• When living things die they decompose.
• Decomposition breaks down organic matter from larger to
smaller molecules.
(See District Strategies: Discussion Guide document in the General
Resources section of the CD.)
2. The teacher will tell the students that they will be investigating
decomposition over the next few weeks.
3. The teacher will distribute a two liter bottle to each lab group. The
bottle will either have been prepared ahead of time by the teacher or
the students will prepare the bottle. (see Advanced Preparation)
4. The students will put organic matter in the bottle.
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5. The students will make observations of the organic matter in the twoliter bottle.
6. Over the next few weeks students will make observations of the
decomposition. Observations should include reading the temperature
within the compost and comparing this temperature to ambient
temperature.
7. The students will record their observations of the decomposition in
their Science Journal.
8. When the students make their observation, the teacher will take this
opportunity to lead the students in a guided discussion. The main
points of the discussion are as follows.
• Decomposition breaks down organic matter from larger to
smaller molecules.
• As decomposition occurs energy is released in the form of heat.
(The temperature within the organic matter of the Decomposition
Column should be slightly higher than room temperature.)
(See District Strategies: Discussion Guide document in the General
Resources section of the CD.)
9. After several weeks of observations the students will complete the
Student Investigation Sheet.
10. As an elaboration the students can vary factors under which
decomposition occurs to see how this affects decay. For example,
students could add different amounts of moisture to different compost
heaps or vary exposure to light to see if these factors affect
decomposition.
11. The teacher can use the rubric provided to evaluate student mastery.
Modifications/Differentiations:
GT
•
ESL/Bilingual
For ideas on teaching vocabulary to ESL students see District
Strategies: Verbal/Visual Word Association document in the
General Resources section of the CD.
Special Education
•
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Assessment:
The formative assessment for this learning experience will include
evaluating how well the students explained and illustrated the decay of
biomass.
The teacher can use the following rubric to evaluate mastery of the
educational objective.
Introduction to Cells Rubric
Score
Criteria:
Student explains
the interaction of
matter and energy
in the decay of
biomass.
Student illustrates
the interaction of
matter and energy
in the decay of
biomass.
4
3
2
1
Student meets all
of the criteria
below.
o Student explains
how big
molecules break
down to smaller
molecules
o Students
explains that
energy is
released as heat
o Student
illustrates big
molecules
breaking down
into smaller
molecules
o Student
illustrates the
release of heat
energy
(See example
below)
Student meets
three of the criteria
below.
o Student explains
how big
molecules break
down to smaller
molecules
o Students
explains that
energy is
released as heat
o Student
illustrates big
molecules
breaking down
into smaller
molecules
o Student
illustrates the
release of heat
energy
(See example
below)
Student meets two
of the criteria
below.
o Student explains
how big
molecules break
down to smaller
molecules
o Students
explains that
energy is
released as heat
o Student
illustrates big
molecules
breaking down
into smaller
molecules
o Student
illustrates the
release of heat
energy
(See example
below)
Student meets one
of the criteria
below.
o Student explains
how big
molecules break
down to smaller
molecules
o Students
explains that
energy is
released as heat
o Student
illustrates big
molecules
breaking down
into smaller
molecules
o Student
illustrates the
release of heat
energy
(See example
below)
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The score obtained from the rubric above can be converted to a science grade.
4=A
3=B
2=C
1=D
Interdisciplinary Connections:
Mathematic Benchmarks that are covered in this lesson:
• A. Identify and apply everyday experiences, to activities in and
outside of school, with other disciplines, and with other
mathematical topics. (TEKS b6.11A)
• E. Use tools such as the formula chart, real objects, manipulatives,
technology or techniques such as mental math, estimation or number
sense to solve problems. (TEKS b6.11D)
• F. Communicate mathematical ideas using language (focusing on
vocabulary), efficient tools, appropriate units, and graphical,
numerical, physical or algebraic mathematical models, (TEKS
b6.12A)
• 22. Solve problems by collecting, organizing, displaying, and
interpreting data. (TEKS b6.10D)
Language Arts Benchmarks that are covered in this lesson:
The student will:
• 1. eliminate barriers to effective listening, including focusing his or
her attention (TEKS 6.1B)
• 3. monitor his/her own understanding of the spoken message and
seek clarification as needed (TEKS 6.2D)
• 4. connect his/her own experiences, information, insights, and ideas
with the experiences of others through speaking and listening.
(TEKS 6.4.A)
• 6. write to express, discover, record, develop, reflect on ideas such as
by composing personal narratives, journals, and/or autobiographies.
(TEKS 6.15A,F)
• 12. write legibly by selecting cursive or manuscript as appropriate.
(TEKS 6.16A)
• 15. write with accurate spelling of syllable constructions, including
closed, open, consonant before –le, and syllable boundary patterns.
(TEKS 6.16C)
Additional Documents:
Class Score Sheet
Student Investigation Sheet (English/Spanish)
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Class Score Sheet
4
Student Name
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Student Investigation Sheet
Name ______________________________
Explain what happens as organic matter decays within the compost heap. You must
include the concepts of matter and energy.
Write the words listed below in the diagram to illustrate the interactions of matter and
energy in the decay of biomass.
BIG MOLECULES, SMALL MOLECULES, DECOMPOSITION, HEAT ENERGY
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Hoja de investigación para el estudiante
Nombre ______________________________
Expliqua lo que sucede durante el decaimiento de materia orgánica dentro del montón de
abono. Debes incluir los conceptos de la materia y la energía.
Escribe las palabras abajo en el esquema para ilustrar las interacciones de la materia y la
energía en el decaimiento de la biomasa.
MOLECULAS GRANDES, MOLECULAS PEQUEÑAS, DECOMPOSICION,
ENERGIA CALÓRICA
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