Does Temperature affect the Refractive Index of water?

1. Does Temperature affect the Refractive Index of water? Chris Greco - Hearne ISD - Hearne, TX Faculty Mentor: Dr. SyBor Wen Mechanical Engineering, Texas A&M

2. 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

3. 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

4. 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

5. 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)

6. 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

7. 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 of • The unit

8. 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

9. Lab setup Interference Pattern Water filled Aluminum channel L Laser Hotplate Interferometer Mirrors

19. Lab setup Interference Pattern Water filled Aluminum channel L Laser Hotplate Interferometer Mirrors

20. Fringe Movement

21. 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)

22. How is the class project Relevant? • Dr. Wen’s Research Lab • In the Classroom

23. 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

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

25. Questions?