Does Temperature affect the
Refractive Index of water?
Chris Greco - Hearne ISD - Hearne, TX
Faculty Mentor:
Dr. Sy Bor Wen
Mechanical Engineering, Texas A&M
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
school
Day 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 writeup
Day 6
–Lab review/Discussion
Post-Test will occur at end of
The unit
Day 5
– Conclusion of lab write
up
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
Lab setup
Interference Pattern
Water filled
Aluminum channel
L
Laser
Hotplate
Interferometer
Mirrors
Lab setup
Interference Pattern
Water filled
Aluminum channel
L
Laser
Hotplate
Interferometer
Mirrors
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?