December 4, 2014 What’s Nano about Light?. Today’s Plan Introduce the International Year of...
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Transcript of December 4, 2014 What’s Nano about Light?. Today’s Plan Introduce the International Year of...
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.”
3http://www.light2015.org/
CommunicationsHealth Economy Environment Social
Celebrating Light
4SPIE, http://www.youtube.com/watch?v=rcoMeWV0jZc
What’s Nano about Light?
5
Stained glass(metallic nanoparticles)
Medicine (nanoparticles, nano-coatings)
Electronics(nanostructures like thin films)
Energy(nanostructures)
SPIE, http://www.youtube.com/watch?v=rcoMeWV0jZc
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
8http://www.light2015.org/
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 Lightor finding scientist partners?
10
Light-related Resources from NISE
11
NanoDays activities
Videos
Programs
http://www.nisenet.org/events/other/international-year-light-2015
So many great resources!
Light-Related ActivitiesMany 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
http://www.nisenet.org/
Light-Related Videos
14
http://vimeo.com/31270439
Nano and Me - Gold
http://vimeo.com/74400132
What’s Nano About Bubbles?
http://www.nisenet.org/
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%
http://design.tutsplus.com/tutorials/draw-a-shiny-make-up-mirror-with-adobe-illustrator--vector-4418
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. [http://www.physicsclassroom.com]
Learn more here: http://www.physicsclassroom.com/class/light/Lesson-2/Color-Subtraction
Nano Gold (Stained Glass)
21http://design.tutsplus.com/tutorials/draw-a-shiny-make-up-mirror-with-adobe-illustrator--vector-4418
Bulk vs Nano Gold
22
Nano Gold
Bulk Gold
http://education.mrsec.wisc.edu/nanolab/gold_uv/index.html#Introduction
Stained glass
Size and Shape Matter
23http://www.horiba.com/scientific/ http://commons.wikimedia.org/wiki/File:Native_gold_nuggets.jpghttp://www.cat.gov.in/technology/laser/lpas/pps.html
At the nanoscale,size matters!
At the nanoscale,shape matters, too!
How are the Colors Created?
24http://edcvs.co/130nfaU
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 cupExample: Lycurgus cupExample: translucent red cupExample: translucent red cup
Color of Reflected vs Transmitted Light
27http://www.shutterstock.com/pic-177894944/stock-photo-group-of-colorful-pink-orange-and-yellow-translucent-plastic-party-cups-with-color-shadows.html
http://www.smithsonianmag.com/history/this-1600-year-old-goblet-shows-that-the-romans-were-nanotechnology-pioneers-787224/?no-ist
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 light Absorbed
Blue light Absorbed
Red light Transmitted
Green light Absorbed and scattered
Blue light Absorbed and scattered
Applications of Nano Gold
28https://vimeo.com/channels/nisenet/66928095
UV Bracelets
29http://design.tutsplus.com/tutorials/draw-a-shiny-make-up-mirror-with-adobe-illustrator--vector-4418
UV Beads
30
How UV Light Affects UV Beads
31http://www.profbunsen.com.au/files/uvdetectionbeads.pdf
• 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
32http://www.profbunsen.com.au/files/uvdetectionbeads.pdf
ShineUV 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
33http://chemwiki.ucdavis.edu/Wikitexts/Prince_George's_Community_College/General_Chemistry_for_Engineering/Unit_1%3A__Atomic_Structure/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
http://nisenet.org/catalog/programs/exploring_properties_-_invisibility
Invisibility Cloak
http://nisenet.org/catalog/media/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!
http://www.rochester.edu/newscenter/
The “Rochester Cloak”
38
4 lenses, with some way to hold them up and align them
The “Rochester Cloak”
39http://www.rochester.edu/newscenter/
The “Rochester Cloak”
40
The “Rochester Cloak”
41
The “Rochester Cloak”
42
Fairly cheap, non-consummable materialsFun way to introduce cloakingPairs 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: http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html
• UV beads
• Good discussion of pigments: http://hermes.mbl.edu/marine_org/images/animals/Limulus/vision/Wald/photosynthesis.html
• Guide from Educational Innovations: http://cdn.teachersource.com/downloads/lesson_pdf/UV-AST.pdf
• Inquiry-based activities
o http://www.carolina.com/teacher-resources/Interactive/activities-with-uv-beads/tr30403.tr
o http://www.carolina.com/teacher-resources/Document/students-plan-an-experiment-using-uv-beads/tr10866.tr
• Sunblock
• Great discussion of all the science behind nano sunblock; includes Powerpoint slides and lesson plans: http://nanosense.sri.com/activities/clearsunscreen/
• U. of Rochester cloaking demo
• Press release: http://www.rochester.edu/newscenter/watch-rochester-cloak-uses-ordinary-lenses-to-hide-objects-across-continuous-range-of-angles-70592/
• Published article: http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-22-24-29465%20
• This group has also developed another cloaking device that uses mirrors: https://www.youtube.com/watch?v=GAmWs6zfTj8 and https://www.youtube.com/watch?v=oJb9RnAVDuE 43
Sunblock
44http://design.tutsplus.com/tutorials/draw-a-shiny-make-up-mirror-with-adobe-illustrator--vector-4418
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?
SkinSkin
Sunscreen/SunblockSunscreen/Sunblock
SkinSkin
Sunscreen/SunblockSunscreen/Sunblock
SkinSkin
Sunscreen/SunblockSunscreen/Sunblock
Absorption Reflection Transmission
Sunscreens vs Sunblocks, Continued
47
How could sunscreen and sunblock work?
SkinSkin
Sunscreen/SunblockSunscreen/Sunblock
SkinSkin
Sunscreen/SunblockSunscreen/Sunblock
SkinSkin
Sunscreen/SunblockSunscreen/Sunblock
Absorption Reflection Transmission
Sunscreens and sunblocks both usually work through absorption of UV raysSunblocks are better because they absorb more of the UV rays
Inorganic Sunblocks Absorb UV Better
48
UVB UVA visible
ideal
Nano Sunblocks
49http://www.tackletour.com/reviewbluelizard.html
Traditional zinc oxide sun blocks are very visible
Modern zinc oxide sun blocks are fairly invisible after application
Nano ZnO and TiO2 Reflect Less Light
50
UVB UVA visible
ideal