What Is The Nanoscale – Size And Scale - MRSEC Education Group

Introduction

It is useful to know the approximate sizes of things. Is something bigger than a bread box? Will it fit through a doorway? Is it as big as it is supposed to be? These are all questions that we may find ourselves asking on a regular basis.

The way people have measured things has varied over time. For example, in Egyptian times, the length of an object was measured in cubits where one cubit corresponded to the distance from one’s elbow to the tip of one’s middle finger. The cubit could be divided into smaller segments, related to the size of different parts of the hand. However, it is easy to imagine that these sizes vary greatly from person to person. A cubit measured on a small child would be very different than one measured on an adult. Through the ages, measurement systems became more standardized. The two primary systems of measurement are the English and the Metric system. Scientists and engineers all use the metric system.

Inclusive Teaching Practices

Inclusive teaching refers to methods that are designed to engage students in learning that is meaningful, relevant, and accessible to all. Creating an inclusive environment is a continuing process that begins before the class starts and is built into the class design. For more resources, go to our Inclusive Teaching Practices page.

Strategies for this background content include:

1. Using examples that are relevant to students’ everyday lives, such as replacing “bread box” in the first paragraph with an X-box or a cereal box.
2. Invite students to identify their own examples of things at various sizes and scales. For example, “What is the largest thing you can think of?” and “What is the tiniest thing you can think of?”
3. Ask for multiple answers and examples about student experiences with size and scale.

The Metric System

In everyday life the English system of measurement with units like feet, gallons and pounds is primarily used in the United States. Scientists and the rest of the world use the metric system of measurement with base units such as the meter, liter and gram. The base unit is then multiplied or divided by powers of ten to represent larger or smaller measurements. Prefixes are used to relate the relative size of the measurement with respect to the base unit. Since the base unit for length is the meter the table below shows all the different prefixes that could be used to express length.

1000 meters (m) would be written as 1 kilometer (km). Other base units can be used as well. For mass, the base unit is the gram (g), so 1/1000th of a g would be written as a 1 milligram (mg). Often is it hard to visualize what those numbers really mean because units in the metric systems are not something we may use in our every day life.

AtomTouch

In order to give students and teachers a more hands-on sense of scale, we developed a free, 3D touchscreen app called AtomTouch. AtomTouch includes a size and scale introductory video, and many engaging and educational activities to give students a real sense of atomic behavior. Play online at BrainPop – AtomTouch or download it for FREE from the App Store or from Google Play.