The Power of Nanoscale

Article excerpt

Two decades after basic research into nanoscience began, nanotechnology is finally delivering on its promised benefits to society. Because nano-sized particles (nanoparticles) can exhibit unique properties, such as luminescence or catalytic behaviors, under specific conditions, students often want to know more about them. To prepare students for the nano era, it is important to include nanoscience and nanotechnology concepts in the middle school curriculum. This article describes activities in which students examine how the ratio of surface area to volume is related to the size of an object, a concept that allows nanoparticles to react quickly with other matter and exhibit unusual properties. Following the 5E model, students explore the characteristics of matter at the nanoscale.

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Engage: Evoking students' ideas

Although most of the world uses the International System of Measurement, commonly referred to as the metric system, many students in the United States are not familiar with it. So, as part of the Engage phase of the lesson, we administer a presurvey to find out what students know about metric units. (Pre-survey is available with this article's online supplemental materials; see Resources.) Students are asked to make a list of various metric units associated with length. Additionally, we give students metric units for length, which they sort from largest to smallest (see online supplemental materials in Resources). We also encourage students to give examples of unit size, such as, "A centimeter is about the size of my pinky nail" and "A meter is about the distance between outstretched arms."

After discussing students' ideas about metric measurement, we found that our students had some familiarity with centimeters and meters but lacked a solid grasp of kilometers, millimeters, micrometers, and nanometers. Our students said they had heard of the units but struggled to give examples. One student asked if a nanometer was related to an iPod Nano, which "comes in a small size." This student was heading in the right direction. After listening to their brief discussion on these units, we knew that we needed to give students referents to assist them in conceptualizing nanoscale objects.

Explore and Explain

To help students understand length (distance) in metric measurements, we ask them to measure a variety of everyday items using millimeter, centimeter, and meter units. Through these activities, students are also asked to find the number of centimeters in a meter, the number of millimeters in a meter, and the number of millimeters in a centimeter. Armed with these experiences, students then explore materials whose sizes are measured in units too small for the human eye, shifting the exploration into a study of the power of nano.

Safety note: We recommend that the following hands-on activities be conducted in class-rooms where eating is permissible, because eating and drinking is prohibited in labs in which hazardous chemicals are used. Remind students that this is a lab, and they should only taste when instructed to do so. Goggles are recommended throughout the activities. A soda can may be used as an example to further demonstrate finding surface area and volume. Be sure to wash and bleach all cans prior to use and tell students not to attempt to drink from, puncture, or squeeze the cans. Alternatively, pictures of soda cans may be used instead. Also, check with students to determine whether they have any medical conditions (e.g., food allergies, diabetes). If so, they should not do the taste test.

CONTENTAREA

Math and science

6-8

BIG IDEA/UNIT

Nanoscale

ESSENTIAL PRE-EXISTING KNOWLEDGE

Basic knowledge about measurements, conversions, and metic units

TIME REQUIRED

60-90 minutes

COST

Under \$50 for each kit

Part 1: Sugar tasting

Teams of three or four students are provided with two small Styrofoam cups labeled A and B. …

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