Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi1 Brazil Problem 16 – Wet and Dark Brazil Problem 16 – Wet and Dark reporter: Thiago Bergamaschi

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi2 Brazil Problem 16 – Wet and Dark Clothes can look darker or change colour when they get wet. Investigate the phenomenon. Optical Microscope View 40X

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi3 Brazil Problem 16 – Wet and Dark Qualitative Analysis Quantitative Analysis Prediction of Relevant Parameters Theoretical Introduction Materials Procedures Data Analysis Experiments Relevant Parameters Conclusion

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi4 Brazil Problem 16 – Wet and Dark Qualitative Analysis: Surface Reflection

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi5 Brazil Problem 16 – Wet and Dark Qualitative Analysis: Surface Reflection

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi6 Brazil Problem 16 – Wet and Dark Quantitative Analysis: Fresnels Equations Nonpolarized Light Total Reflectance Perpendicular Polarization n1n1 n2n2 θ1θ1 Parallel Polarization θ1θ1 θ2θ2

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi7 Brazil Problem 16 – Wet and Dark Qualitative Analysis: Material Reflection Incident Medium´s Refraction Index Origin Medium´s Refraction Index Reflectance [%]

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi8 Brazil Problem 16 – Wet and Dark Dry Cloth Wet Cloth Qualitative Analysis: Material Reflection

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi9 Brazil Problem 16 – Wet and Dark QuantitativeAnalysis: Surface Reflection LAMBERT’S REFLECTION LAW 1- R l 1- R l (1-a) 1- R l (1-a)p

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi10 Brazil Problem 16 – Wet and Dark

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi11 Brazil Problem 16 – Wet and Dark Prediction of Relevant Parameters Maximizing Liquid Cloth Reflections, instead of Cloth air Minimizing Reflection by Fresnels law Increases thread reflections Maximizes Reflection Minimizes “darkening” effect

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi12 Brazil Problem 16 – Wet and Dark Resistance (Ω) Illumination (lux) k 10k 100k 1M 10M Cadmium sulphide track Light-Dependent Resistor

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi13 Brazil Problem 16 – Wet and Dark Varied Cloths Multimeter (Δx=±0.01kΩ) Light Dependent Resistor Lantern Measuring Cylinder (Δx= ±0.1mL) Pipette (Δx=±0.1mL) Water Glicerin Materials

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi14 Brazil Problem 16 – Wet and Dark Connect the Multimeter with the LDR In a isolated room (without secondary light sources), measure the emerging light intensity Vary the Water Volume in the Cloth (0.0, 1.0, 2.5, 5.0, 7.5, 10.0), as well as color, liquid and cloth thickness Procedures

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi15 Brazil Problem 16 – Wet and Dark Take photos of a standardized area, dry and with a (10.0 ± 0.1) mL water volume. Plot the corresponding histograms and compare the photos. Experiment 2

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi16 Brazil Problem 16 – Wet and Dark Photos

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi17 Brazil Problem 16 – Wet and Dark Photos

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi18 Brazil Problem 16 – Wet and Dark Data Analysis Original Color High Dry Absortion Minimizing the Phenomenon Cloth Thickness Refraction Index Original Color Cloth Material Cloth Permeability LDR Distance Histograms White Yellow Green Red Blue Purple

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi19 Brazil Problem 16 – Wet and Dark Higher the Water Volume Higher the Transmitance Maximizing the Phenomenon Data Analysis Cloth Thickness Refraction Index Original Color Cloth Material Cloth Permeability LDR Distance Histograms Applied Water Volume Variation Liquid Volume [mL] Transmitance [%] Blue White Yellow Green Red Purple

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi20 Brazil Problem 16 – Wet and Dark Thicker the Cloth Higher the Material Reflection Minimizing the Phenomenon Data Analysis Cloth Thickness Refraction Index Original Color Cloth Material Cloth Permeability LDR Distance Histograms

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi21 Brazil Problem 16 – Wet and Dark Transmitance [%] Liquid Volume [mL] Refraction Index Comparison Absorbtion [%] Liquid Volume [mL] Refraction Index Comparison Refraction Index Water: Glicerin: Closer the Liquid´s Refraction Index to the cloth´s Water Glicerin Lower the Material Reflection Maximizing the Phenomenon Data Analysis Cloth Thickness Refraction Index Original Color Cloth Material Cloth Permeability LDR Distance Histograms

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi22 Brazil Problem 16 – Wet and Dark Data Analysis Higher Liquid Temperature Lower the Refraction Index Minimizing the Phenomenon Cloth Thickness Refraction Index Original Color Cloth Material Cloth Permeability LDR Distance Histograms

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi23 Brazil Problem 16 – Wet and Dark Dry Absortion Data Analysis Refraction Index closer to water´s Cloth Thickness Refraction Index Original Color Cloth Material Cloth Permeability LDR Distance Histograms

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi24 Brazil Problem 16 – Wet and Dark Little Variation Data Analysis Cloth Thickness Refraction Index Original Color Cloth Material Cloth Permeability LDR Distance Histograms

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi25 Brazil Problem 16 – Wet and Dark Data Analysis Impermeability Maximizing Air-Cloth Material Reflection Minimizing the Phenomenon Data Analysis Cloth Thickness Refraction Index Original Color Cloth Material Cloth Permeability LDR Distance Histograms

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi26 Brazil Problem 16 – Wet and Dark Data Analysis Falls off Quadraticly Lower Light Intensity Transmitted and Reflected Cloth Thickness Refraction Index Original Color Cloth Material Cloth Permeability LDR Distance Histograms

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi27 Brazil Problem 16 – Wet and Dark Data Analysis Cloth Thickness Refraction Index Original Color Cloth Material Cloth Permeability LDR Distance Histograms

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi28 Brazil Problem 16 – Wet and Dark Summary: Theoretical Introduction

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi29 Brazil Problem 16 – Wet and Dark Summary: Experiments

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi30 Brazil Problem 16 – Wet and Dark Conclusion The Bigger, the Better The Smaller, the Better

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi31 Brazil Problem 16 – Wet and Dark Bibliografy Link Linkhttp://axpfep1.if.usp.br/~otavianoporquecoisasmolhadasficammaisescuras. htmlhttp://axpfep1.if.usp.br/~otavianoporquecoisasmolhadasficammaisescuras. html Link Lekner, John. Dorf, Michael C. Why some things are darker when wet., APPLIED OPTICS, Vol.23, No7, Link Link

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi32 Brazil Problem 16 – Wet and Dark Thank you!Thank you!

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi33 Brazil Problem 16 – Wet and Dark Appendix 1: S Polarized Light Polarized, Thus Lower Light Intensity Darker, though less intense The more Inclined, higher Reflectance Minimizing the Phenomenon

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi34 Brazil Problem 16 – Wet and Dark Appendix 2: P Polarized Light Polarized, Thus Lower Light Intensity Darker, though less intense R follows a peculiar format Where R is minimized, T is Maximized

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi35 Brazil Problem 16 – Wet and Dark Appendix 3: Incidence Angle Incident Angle Increase Higher Reflectance Minimizing the Phenomenon

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi36 Brazil Problem 16 – Wet and Dark Appendix 4: Light Source Comparison Higher Focalizing power

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi37 Brazil Problem 16 – Wet and Dark Appendix 5: Wet, Transparent, White Cloths Coisas molhadas são, usualmente, mais escuras, quando as observamos sob iluminação, pois a luz penetra mais facilmente do que quando secas. Areia, papel, cimento, terra, etc, têm essa propriedade. Mas, se a luz penetra mais profundamente em coisas molhadas, então elas podem ser mais transparentes ou translúcidas do que quando secas? Sim. Pegue um pedaço de papel de cozinha (ou guardanapo de papel, ou papel de enxugar a mão) e, observando contra uma fonte de luz, note que, se molhado, mais luz o atravessa. O mesmo ocorre com tecidos: se molhados, ficam mais escuros quando são observados sob a luz... mas ficam também mais transparentes, o que, constrangedoramente, ocorre quando se mergulha na água com um tecido inadequado Higher Transmitance Lower Reflectance Darker and Transparent

Team of Brazil Problem ## Title Diego de Moura, Felipe de Melo, Matheus Camacho, Thiago Bergamaschi, Thiago KalifeNakhon Ratchasima, 27 June – 4 July 2015 Reporter: Thiago Bergamaschi38 Brazil Problem 16 – Wet and Dark Appendix 5: Brewster´s Angle