December 4, 2014 What’s Nano about Light?

Today’s Plan Introduce the International Year of Light (IYL) Discuss possible partners for IYL Present NISE resources for IYL Describe the science behind two NanoDays activities If time, a surprise! 2

International Year of Light (IYL) “A global initiative adopted by the United Nations to raise awareness of how optical technologies promote sustainable development and provide solutions to worldwide challenges in energy, education, agriculture, communications and health.” “The science and applications of light creates revolutionary - but often unseen - technologies that directly improve quality of life worldwide.” 3 CommunicationsHealthEconomyEnvironmentSocial

Celebrating Light 4 SPIE,

What’s Nano about Light? 5 Stained glass (metallic nanoparticles) Medicine (nanoparticles, nano-coatings) Electronics (nanostructures like thin films) Energy (nanostructures) SPIE,

Why Should You Care About the IYL? Kids are naturally interested in light and color This is a great opportunity for partnering with scientists There are tons of great NISE resources (activities and videos) related to light 6

Check-in Time (1)Are you interested in trying to bring in scientists for IYL events? (2)Do you already know scientists you could contact? 7

IYL Partner Organizations 8

Finding a Partner IYL is a great time to approach scientists, because they’re supposed to be involved in outreach What kinds of scientists/organizations are involved in IYL? NISE has contacts in SPIE and OSA 9 Physicists Material scientists/engineers Electrical engineers Optical engineers SPIE (physicists/engineers) APS (physicists) OSA (physicists and engineers) IEEE (engineers) APS = American Physical Society, OSA = Optical Society of America, IEEE = Institute of Electrical and Electronics Engineers

Check-in Time Any general questions about the International Year of Light or finding scientist partners? 10

Light-related Resources from NISE 11 NanoDays activities Videos Programs ternational-year-light-2015 So many great resources!

Light-Related Activities Many of these activities aren’t just related to light—they’re also an excellent introduction to everything that’s cool and unique about nano 12

Light-related Topics: Examples Light in nature Butterfly Thin Films Bubbles Nanoscale-phenomena Sunblock Nano Gold Invisibility New technologies/devices Liquid crystal displays Thin Films 13

Light-Related Videos 14 Nano and Me - Gold What’s Nano About Bubbles?

Check-in Time (1)Do you have a favorite light-related activity from NISE? If so, what is it? 15

Check-in Time (1)Do you have a favorite light-related activity from NISE? If so, what is it? (2)Do you find it challenging to describe the science behind any of NISE’s light-related activities? If so, which one(s)? 16

Absorption, Reflection, and Transmission 17 Sunlight and other white light contains all colors When light hits an object, it can be Absorbed Reflected Transmitted In the case of raspberries Green and blue are strongly absorbed Red is only partially absorbed

Absorption, Reflection, and Transmission 18 Absorption + Reflection + Transmission = 100%

Check-in Time Why does a red apple look red? (1)It absorbs most of the red light from the sun (2)It reflects most of the red light from the sun (3)It transmits most of the red light from the sun 19

Why does a red apple look red? (1)It absorbs most of the red light from the sun (2)It reflects most of the red light from the sun (3)It transmits most of the red light from the sun 20 The color of an object is not actually within the object itself. Rather, the color is in the light that shines upon it and is ultimately reflected or transmitted to our eyes. [ Learn more here:

Nano Gold (Stained Glass) 21

Bulk vs Nano Gold 22 Nano Gold Bulk Gold Stained glass

Size and Shape Matter At the nanoscale, size matters! At the nanoscale, shape matters, too!

How are the Colors Created? 24

Resonance Causes Absorption & Scattering Bells are a great analogy because they ring due to resonance (reverberation) We usually think about resonance in terms of sound waves, but other waves can also undergo resonance Metallic surfaces have surface plasmons – delocalized electrons These electrons have wave properties 25

Resonance Causes Absorption & Scattering Light of a specific wavelength can interact strongly with these delocalized electrons, making them resonate We call this surface plasmon resonance Light that interacts strongly is absorbed and/or scattered; other wavelengths of light are mainly transmitted Produces vibrant colors To learn more about scattering, read about how scattering causes the sky to look blue 26

Example: Lycurgus cup Example: translucent red cup Color of Reflected vs Transmitted Light But nano gold and silver have different colors in reflected vs. transmitted light Usually, reflected and transmitted colors are the same Red light Reflected and transmitted Green lightAbsorbed Blue lightAbsorbed Red lightTransmitted Green light Absorbed and scattered Blue light Absorbed and scattered

Applications of Nano Gold 28

UV Bracelets 29

UV Beads 30

How UV Light Affects UV Beads 31 Originally beads are colorless because the molecules aren’t good at absorbing light UV light breaks bonds and changes the structure of the molecules This makes it possible for them to absorb light UV light

UV Beads When not exposed to UV light, the molecules will convert back to their original forms, and beads will once again appear clear For older students, could investigate how temperature and other variables affect this process 32 Shine UV light Turn off UV light, then wait

Chemistry Behind Color How do pigment and dye molecules absorb light? Certain wavelengths of light interact with electrons and promote the electrons to a higher energy level These wavelengths (colors) are absorbed 33 tructure/Chapter_2%3A_Atomic_Structure/Chapter_2.3%3A_Atomic_Spectra_and_Models_of_the_Atom

UV Beads 34 High energy Low energy 5 eV Before UV exposure, energy gaps are larger Visible light doesn’t have enough energy to promote an electron

UV Beads 35 High energy Low energy High energy Low energy 5 eV 2.3 eV Before UV exposure, energy gaps are larger Visible light doesn’t have enough energy to promote an electron After UV exposure, energy gaps are smaller Certain colors of visible light have enough energy to promote electrons [Orange bead]

A New Invisibility Demo! 36 Exploring Properties - Invisibility perties_-_invisibility Invisibility Cloak Just in time for IYL, there’s a new invisibility (cloaking) demo you can try!

A New Invisibility Demo! 37 Just in time for IYL, there’s a new invisibility (cloaking) demo you can try!

The “Rochester Cloak” 38 4 lenses, with some way to hold them up and align them

The “Rochester Cloak” 39

The “Rochester Cloak” 40

The “Rochester Cloak” 41

The “Rochester Cloak” 42 Fairly cheap, non-consummable materials Fun way to introduce cloaking Pairs well with other NISE materials Hard to keep lenses aligned (especially near a two-year-old!) May be hard to explain

Resources Stained glass (nano gold) Good discussion of scattering: UV beads Good discussion of pigments: Guide from Educational Innovations: Inquiry-based activities o o Sunblock Great discussion of all the science behind nano sunblock; includes Powerpoint slides and lesson plans: U. of Rochester cloaking demo Press release: across-continuous-range-of-angles-70592/ across-continuous-range-of-angles-70592/ Published article: This group has also developed another cloaking device that uses mirrors: and

Sunblock 44

Sunscreens vs Sunblocks 45 Sunscreens use chemicals There are also sunblocks that use minerals like zinc oxide or titanium dioxide nisenet.org vitaderminstitute.com/

Sunscreens vs Sunblocks, Continued 46 How could sunscreen and sunblock work? Skin Sunscreen/Sunblock Skin Sunscreen/Sunblock Skin Sunscreen/Sunblock AbsorptionReflectionTransmission

Sunscreens vs Sunblocks, Continued 47 How could sunscreen and sunblock work? Skin Sunscreen/Sunblock Skin Sunscreen/Sunblock Skin Sunscreen/Sunblock AbsorptionReflectionTransmission Sunscreens and sunblocks both usually work through absorption of UV rays Sunblocks are better because they absorb more of the UV rays

Inorganic Sunblocks Absorb UV Better 48 UVBUVA visible ideal

Nano Sunblocks 49 Traditional zinc oxide sun blocks are very visible Modern zinc oxide sun blocks are fairly invisible after application

Nano ZnO and TiO 2 Reflect Less Light 50 UVBUVA visible ideal