Does Temperature affect the Refractive Index of water?

Faculty Mentor:Dr. Sy Bor Wen

Mechanical Engineering, Texas A&M

Chris Greco - Hearne ISD - Hearne, TX

Research Question Re-Cap

– Generating differing types of nano particles– Using laser ablation

– Determining the effectiveness of a zone plate as a lead in to creating nano-optic devices– Experimental research in nano patterning

Using thermal reflectance as a non-contact measuring tool to find temperature– Via time resolved interferometry

Modified Sagnac Interferometer

Will allow for the non contact measurement of temperature of the nsom probe during pulsed heating through the nano second laser

Will be compared to existing simulations of Dr. Wen’s David et al, optic letters 1999

Why Measure Refraction?

– Lenses– Fiber Optics– Telescopes– Computer software

enhancement of images (adaptive optics)

http://illuminatingreality.com/wp-content/uploads/2009/08/distortion.jpg

http://wwwmaths.anu.edu.au/~stals/galaxy_with_and_without_ao.png

Project Timeline

• 6 class days for the project. 17 days for the entire unit (Properties and Examples of Waves)– Intro (1 day)– Project begins at day 8 of the

unit– Set up and Execution (2.5

days)– Lab write up (1.5 days)– Review and post-test(1 day)

Day by Day Breakdown

Pre-test at beginning of schoolDay 1

– Pre test– Review key concepts– Introduce new concepts– Laser safety– Introduce the engineering

question– Does the refractive index of

water go up when you heat it or cool it from room temp?..Hook it to submarine sonar in varying ocean temps

Day 2– Intro to laser setup– Students get materials

to set up experiment

Day 3– Conduct Experiment– Measuring/graphing

refractive index of water as determined by change of temperature

Day 4– Conclude

Experiment/data gathering

– Begin formal lab write-up

Day 5– Conclusion of lab write

up

Day 6–Lab review/Discussion

Post-Test will occur at end ofThe unit

Necessary Materials/Equations

• Laser pointer• Mirrors• Kinetic mounts• Interferometer• Negative lens• Aluminum water

channel with glass ends

• OPL=2Ln• ∆=2L(n-1.3353)• ∆ = Nλ• n = (Nλ)/2L +1.3353• n = (Nλ)/2 + λ/4L +

1.3353

Laser

Lab setup

Interferometer

Interference Pattern

Mirrors

Water filled Aluminum channel

Hotplate

L

Laser

Lab setup

Interferometer

Interference Pattern

Mirrors

Water filled Aluminum channel

Hotplate

L

Fringe Movement

Possible Questions for Pre/Post test

• 1. Which is not a normal property of waves?

• a. energy• b. wavelength• c. mass• d. speed• e. frequency

• 2. Which of the following is the amplitude?

• A• B• C• D (circle the

correct letter)

How is the class project Relevant?

• Dr. Wen’s Research Lab

• In the Classroom

Bridging Into the Research Lab

In the Lab– research into light (laser)

behavior in different materials

– Using experiments to provide information in order to assess a hypothesis

– Using optic devices– producing papers on

results

In the Classroom– Computing the refraction of

water at different temps using lasers

– Physics Teks 7b (understanding how heat energy can increase disorder) and 8a (understanding properties of waves)

– Scientific Method– Setting up the experiment– Writing a formal lab report

– Physics Teks 1ab,2a-f,3a-c

Acknowledgements

National Science Foundation (NSF) Nuclear Power Institute (NPI) Texas Workforce Commission (TWC) Chevron E3 Dr. Wen and his research staff

Questions?