David Mortimer Physics Teacher Del Rio High School SFDR-CISD

Haiyan Yang, Ph.D. Xinghang Zhang,

Ph.D.

Specific Application of Technology

◦ The concept of the application of material onto another surface to change or enhance, aka., exploit, materials.

Future applications

-The how and why of Vacuum Systems to include the gas laws.

-The stacking of atomic crystal structures.

-Testing of material properties.

TEKS B1-4, Conducting field and

lab experiments, building knowledge by physical, mathematical, and conceptual models, understanding the whole, Investigations led to changing understanding.

C,1,a,b, Lab Safety C,2,a-e, use scientific

method C,3,a-d, critical thinking and

problem solving. C,4,a, laws governing

motion

TAKS Objective 1, The nature of

Science Objective 5, Motion, Force,

and Energy

Pre-TestingBefore starting this lesson the teacher would have covered the following:

1. Changes in Motiona. Force is a vector quantity that causes changes in motion.b. Force can act either through the physical contact of two objects or at a

distance.c. Free body diagrams.

2. Newton’s first lawa. “Law of inertia”-nothing will change what it is doing unless a net

force>0 acts upon it.3. Newton’s second law

a. Force = mass X acceleration4. Newton’s third law

a. Rocket law – for every action there is an equal and opposite reaction.

Students will be asked to come up with a plan to test certain materials that are applied to other materials so that they can test for the best reduction in friction.

Students will be shown situations where the least friction will be of benefit to a consumer.

Students will compete for longest slide at the end of the lab experience.

Dear Valued Future Vendor:

XYZ Skateboard Company is accepting bids for a thin film product that will lessen the coefficient of friction on our line of very popular skateboards. XYZ Skateboard began in 1992 and has been know from the very beginning to be an innovator in skateboard design. This process is expected to be very competitive and the chosen bidder will likely reap financial and personal reward. Since we believe in the common man and his innovative ability, the following is provided to help you, the bidder, to better understand the concepts that we are dealing with. We will be offering a class where you may learn to test for the coefficient of friction, how hard is it to get something to move, and, also, you may test your own samples in our state of the art testing facilities.

XYZ Skateboard Co.Application for bids

The goal of this lab is to determine the static and kinetic coefficient of friction for various materials in contact with one another and then apply a coating of some other materials to determine if the coefficient increases or decreases.

The student will also try to show the effect of increased mass, increased/decreased surface contact, changes in the angle of the inclined board, and changes in velocity.

The student will also be making conclusions about which materials work best together in different situations.

The student will be asked to rank your findings and a contest for the best sliding mixture of materials will occur at the completion of the lab.

Fourier Lab Pro Data loggers

Distance Sensor Force Sensor 4’ shelf Ring stand Set of masses Aluminum block Steel block Brass block

3-Petri dishes Clamp Protractor Meter stick Graphing calculator Balance Scale Teflon Spray Silicon spray Graphite String

1) Clean up your block so that it has the least amount of friction.

2) Place wax paper onto the scale and zero out the scale.3) Find the mass (m) of the first block.4) Place the first block into the set up.5) Calculate Fgrav=m*ag and enter into the data sheet.

If the weight is on an incline, the normal force will be reduced by the cosine of the incline angle. The equation is

N = wcos(a) where: N is the normal force on the incline W is the weight, weight is a force, the force of gravity, Fgrav=mass*acceleration of gravity. a is the incline angle cos(a) is the cosine of the angle a Wcos(a) is W times cos(a)

6) Calculate the normal force, Fnormal=Fgrav *cosΘ and enter into the data sheet. Cos (0) = 1

7) Connect the force sensor to the string and pull, note what the force is when the sample starts to move. This is your Fapplied. Enter into the data sheet.

8) Pull the mass again with constant velocity, enter the force required to keep the block moving.

9) Replace the block onto the board and raise the board until the block begins to slide. Note the angle at which the block began to slide.

10) Calculate the Fnormal using your new angle.

11) Repeat steps 3-10 for each set of blocks.12) We are now going to apply a thin coat of three different

materials, Teflon spray, Silicon spray, and graphite to see how these coating affect the coefficient of friction. It is very important that you clean the sample very well after each application of material.

13) Place the first sample into the Petri dish with the graphite. Move it around to completely cover the bottom of the sample. We want a thin film. Excess material should not be evident. The thinner the layer the better.

14) Repeat steps 3-10 using the new film and note your results.

Material A/mass/ position/coating if applicable

Material B

Fgrav

=mag

Applied force to start movementFstatic friction

Applied force to maintain movementFKineticriction

Calculated FNormal=Fgrav

*cosΘ

Angle of board

Fnormal

on angle

CalcµStatic= Fstatic

friction/ FNormal

Calcµkinetic= Fkinetic

friction/ FNormal

Ex., aluminum, .5N,wide side forward, no coat

Wood Shelf

Ex., Aluminum, thin side forward,.55N, Graphite

Steel bar

Static Force

Kinetic Force

F=k*distance

y = 0.0238x + 34.184

R2 = 0.9934

39

40

41

42

43

44

45

46

47

48

0 100 200 300 400 500 600

Distance

Fo

rce

Linear ( )

Force Distance

40 257

41 280

42 327

43 365

44 413

45 446

46 489

47 550

Post Testing Student should have mastered the concepts presented in the pre-testing phase.

Newton’s laws and Force Diagrams

The student should have a clear understanding of the difference between static and kinetic friction. The student should be able to determine the coefficient of static friction.

The student should be able to make informed choices given information about coefficients of friction to choose the right supplies for the right job.

Students should realize that they do not need sophisticated equipment to determine forces.

Most importantly, students should realize that they have seen these concepts all of their lives and realize that we are only reinforcing what they already know.

Generally, what is the normal force? What is the applied force? When does something begin to slide? Why does it not slide originally? Is the normal force more or less when the board is inclined? What helps make it slide when it is on an incline? Is the µkinetic ever bigger than the µStatic? Why don’t we consider air resistance? Draw a free body diagram of the horizontal plane and another one for the

angled plane. Label all forces that are applicable. Is the coefficient of friction constant depending only on the types of

surface in contact? (Remember it is very difficult to reproduce exactly the same value for the coefficient of friction on each run.)

Does the surface area, positioning, change the coefficient of friction? Explain.

Does the normal force change the coefficient of friction? What are your sources of experimental error?

04/19/23

Roy Araujo : Functional Nitride Thin FilmsPeru

Joon Hwan Lee Optical , transparency, transmittanceSouth Korea

Ick Chan Kim Prop. Of film through thickness change South Korea

Zhenxing Bi Deposition PatternsChina

Jong Sik Yoon Functional Oxide Thin Films South Korea

Jie (Joyce) Wang High Temperature Super Conductor

Harrison Tsai same as Joyce

Sunmee Cho, South Korea

Xinghang Zhang, Ph.D.

Haiyan Wang, Ph.D.

XYZ Skateboard Inc.

National Science Foundation

All of the TAMU faculty and Staff

Texas A&M Giggem Aggies

Dr. Wang and Dr. Zhang

Zhenxing Bi Ph.D. Candidate

Joon Hwan M.S. Candidate

All of the rest of the Pulsed Laser Deposition laboratory candidates

Ms. Crystal Woods

All of the E3 Participants

Dixie Chicken