A Fine Measurement Machine

Integrating Nanotechnology into

the K-12 STEM Curriculum

Mort Sternheim: mort@umassk12.net

Rob Snyder: snyder@umassk12.net

In spite of their different goals, science and technology have become closely, even inextricably, related in many fields. The instruments that scientists use, such as the microscope, balance, and chronometer, result from the application of technology/engineering........

Page 8: http://www.doe.mass.edu/frameworks/scitech/1006.doc

Atomic Force Microscopes (AFMs) are used Atomic Force Microscopes (AFMs) are used to make nanoscale measurementsto make nanoscale measurements

http://en.wikipedia.org/wiki/File:Atomic_force_microscope_by_Zureks.jpg

An AFM generated this image of the An AFM generated this image of the ionic crystal lattice array of sodium chloride.ionic crystal lattice array of sodium chloride.

http://en.wikipedia.org/wiki/Image:AFM_view_of_sodium_chloride.gif

This example of a schematic drawing reveals This example of a schematic drawing reveals some essential components of an AFM.some essential components of an AFM.

http://en.wikipedia.org/wiki/Image:Atomic_force_microscope_block_diagram.png

Key features of an AFM include:Key features of an AFM include:

A flexible cantilever that exerts a small amount of A flexible cantilever that exerts a small amount of downward force on an object so that the object is not downward force on an object so that the object is not damageddamaged..

A mirror that creates a long pathway for reflected light to A mirror that creates a long pathway for reflected light to travel so that the motion of the tip at the and of the travel so that the motion of the tip at the and of the cantilever is multiplied.cantilever is multiplied.

A lever mechanism can model the process A lever mechanism can model the process of making measurements with an AFM.of making measurements with an AFM.

Laser PointerRuler

Lever supportmirror

Hanging mass

The activity document provides The activity document provides directions for:directions for:

• Assembling a lever mechanism that can measure the thinness of an object.

• Calibrating the lever mechanism.• Determining how much the level

mechanism multiplies motion.• Developing a strategy to map an uneven

surface.

If a thin object moves under one end of the If a thin object moves under one end of the lever arm, it causes the lever arm to move a short lever arm, it causes the lever arm to move a short distance and the point of light on the ruler moves a distance and the point of light on the ruler moves a greater distance. greater distance.

The reflected light beam now reaches a different point on the ruler.

A hanging mass can be placed in a position on the A hanging mass can be placed in a position on the short arm of the lever so that the long lever arm short arm of the lever so that the long lever arm does not exert a lot of downward force on the does not exert a lot of downward force on the

object that is being measured.object that is being measured.

The lever needs to be able to respond to subtle changes in thinness.

An object of a known thinness can be used to An object of a known thinness can be used to calibrate the measurement machine.calibrate the measurement machine.

The calibration reveals the relationship between the movement of the lever and the movement of the point of light on the ruler.

Tasks for team members to accomplish.Tasks for team members to accomplish.

• Organize a work area.• Coordinating your group’s movements with

other groups.• Assembling the machine.• Managing the experimental procedure.• Working with the laser pointer carefully.• Collecting and recording data.• Keeping the lever assembly stable.

The Analyzing Pathways of Light document explores the laws of reflection.

Angle of Incidence

Angle of Reflection

Normal Line

Mathematical relationships can be discovered.

.cantilever

laser

Long light path and a short cantilever gives large amplification

d1

d2

L1

L2

pivotpoint

The distance amplification d2/ d1 is proportional to L2/ L1

The Balanced Torques document explores another aspect of a lever mechanism.

Point of Rotation

Some questions Some questions

How was the fine measurement machine How was the fine measurement machine similar to the design of an Atomic Force similar to the design of an Atomic Force Microscope?Microscope?

How was the fine measurement machine How was the fine measurement machine different from the design of an AFM?different from the design of an AFM?

Why do we need to minimize the amount of Why do we need to minimize the amount of downward force acting on an object being downward force acting on an object being mapped?mapped?

A Few More Questions

How do you know when the measurement machine reaches an equilibrium?

What forces are involved when the model of an AFM is mapping an object?

What additional technologies are associated with using an AFM to collect data?

How would you change the design of the measurement machine to make it more effective?

UMass Amherst NanotechnologyCurriculum Resources are available at

http://umassk12.net/nano/

Examples of Activities, Teacher Guides, Worksheets, PowerPoints and Multimedia Module Include:

The Fine Measurement Machine as a model of an Atomic Force Microscope

An Oleic Acid Thin Film ActivityNanoscale ElectrodepositionGel DiffusionThe Nanotechnology of SunscreenNanoscale Powers of Ten