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Students will learn that size does matter. They will investigate how changes in the shape or size of an object affect its surface area to volume ratio (SA/V), which can change dramatically in the nanoscale. When they complete the Activities, they will apply this knowledge to design an “exploding” liquid geyser. By incorporating everyday materials into science lessons, the Materials World Modules (MWM) program at Northwestern University has found the solution to getting students excited about learning science while helping teachers meet national and state education standards. The modules are easy to organize and inexpensive to run. They can be incorporated into any science class because of the breadth of subjects covered in the Activity and Design Project sections. Each module is a supplemental science unit that takes 1-3 weeks of class time (approximately 10 hours) to complete. |
Module At-a-Glance
Module At-a-Glance
Activity 1: Measurement and Tools
The activity begins by a review of the SI units and metric prefixes, which are especially important when expressing numbers in scientific notation for extremely small and large objects. Students learn that tools and instruments determine what is accessible to measure, detect, and manipulate with precision and accuracy, as well as understand the significance that a standardized set of units is needed to effectively communicate data.
Activity 2: Size Dependent Properties
The importance of an object’s size manifests itself most significantly through interaction of its surfaces with the surrounding environment. This “hook”activity presents some intriguing phenomena that pique students’ interest in surface area effects, i.e., how physical form and size of a solid influences the degree to which it interacts with its environment. They find that the more finely divided (or more spread out) a solid is, the more surface is available for
this interaction.
Activity 3: Powers of 10 and Scale
Students get a feel for dimensions (or size of objects) that are very different from our ordinary experience, with examples in the range of 109 to 10-9 meters. A most useful concept for this purpose is scale. Activity 2 also emphasizes the representation of scale in ways that make it easy to understand (effect of changing size by a factor of 10, or stepwise change in orders of magnitude).
Activity 4: Surface Area and Volume
To help students realize how and why surface area to volume ratio (SA/V) changes dramatically in the nanometer scale, students construct objects that varies in size, as well as shape. They begin by looking at twodimensional (2-D) behaviors involving perimeter and area, which has analogous relationship as surface area and volume, followed by exploration of how SA/V changes with the size or shape of 3-D objects.
Design Project: Designing a Liquid Geyser
Students are challenged to apply the concept of SA/V to a real-life experiment. They begin by evaluating the familiar “Coke™ fountain” experiment resulting from the heterogeneous nucleation of carbon dioxide gas on the surface of Mentos™ candy. Their task is to increase the SA/V and create a high surface area alternative to Mentos to make the soda “geyser” go higher.
Connecting to Your Curriculum
Connecting to Your Curriculum
Materials World Modules are designed to be easily incorporated into any middle school science or high school science lab or lecture course. The chart below lists the subjects covered in the Activity and Design Project sections of this module.
Physics & Physical Science
Chemistry
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Mathematics
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Biology and Life Science
Language Arts
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Standards Alignment
AAAS Benchmark Standards |
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NSES Standards |
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NCTM Standards
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Grades 9-12 |
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Grades 9-12 |
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Grades 9-12
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1. Nature of Science |
A. Science as Inquiry |
Numbers & Operations
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Scientific inquiry |
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Ability to do scientific inquiry |
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Understanding number relations |
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2. The Physical Setting |
B. Physical Science |
Geometry |
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Structure of Matter |
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Chemical Reactions |
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Analyze characteristics and properties of two- and three-dimensional geometric shapes
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9. The Mathematical World |
E. Science and Technology |
Use visualization, spatial reasoning, and geometric modeling |
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Symbolic Relationships |
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Abilities of Technological Design |
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Representation |
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Shapes |
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Process Standard V |
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11. Common Themes |
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Scale |
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