Rotting Apples
Phenomenon:
An apple that falls from a tree begins to rot on the ground.
Student Task:
Construct an explanation for what causes an apple to rot.
Model
Students develop a model to describe how matter cycles between plants, animals, and decomposers in a garden ecosystem.
Investigate
Students plan and carry out an investigation to determine the effect of different variables on a rotting apple.
Obtain Information
Students read to obtain information about how food scraps placed in a compost pile change into rich soil for a garden.
Analyze Data
N/A
Explanation:
An apple rots because tiny microorganisms (fungi and bacteria) break down the matter in dead plants and animals to obtain energy. Some of the decomposed matter is left behind in the soil where it can be used again by plants growing in the garden. Thus matter cycles among living and nonliving components of a garden ecosystem.
Application (Optional STEM Project):
Students design a compost system and start a lunch composting program at their school, tracking pounds of food scraps collected over time.
NGSS Standard:
5-LS2-1 Develop a model to describe the movement of matter among plants, animals, decomposers, and the environment.
[Clarification Statement: Emphasis is on the idea that matter that is not food (air, water, decomposed materials in soil) is changed by plants into matter that is food. Examples of systems could include organisms, ecosystems, and the Earth.]
MS-LS2-3 Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem.
[Clarification Statement: Emphasis is on describing the conservation of matter and flow of energy into and out of various ecosystems, and on defining the boundaries of the system.]
Utah SEEd Standard:
6.4.3 Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem.
[Emphasize food webs and the role of producers, consumers, and decomposers in various ecosystems.]
Recommended Teaching Sequence:
Day 1: Students plan and carry out an investigation to determine the effect of different variables on a rotting apple.
TWO OR THREE WEEKS LATER
Day 2: Students record observations of their compost bags. Students read to obtain information about how food scraps placed in a compost pile change into rich soil for a garden.
Day 3: Students develop a model to describe how matter cycles between plants, animals, and decomposers in a garden ecosystem. Students construct an explanation for what causes an apple to rot. Students support their explanation using evidence from their own investigation.
Formative Assessment:
Use what students have written in their science notebooks as a formative assessment, including the observations they recorded and their written explanation for the phenomenon. Do students understand that matter cycles among the living and nonliving components of a garden ecosystem? Do students understand the important role that decomposers play in the environment?
Lesson Contributor:
April Mitchell, Science Coach, Salt Lake City School District