Transcript Slides from the brown-bag

What’s Nano about Light?
December 4, 2014
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.”
Health
Communications
http://www.light2015.org/
Economy
Environment
Social
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Celebrating Light
SPIE, http://www.youtube.com/watch?v=rcoMeWV0jZc
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What’s Nano about Light?
Electronics
(nanostructures like thin films)
Stained glass
(metallic nanoparticles)
Medicine
(nanoparticles, nano-coatings)
SPIE, http://www.youtube.com/watch?v=rcoMeWV0jZc
Energy
(nanostructures)
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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
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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?
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IYL Partner Organizations
http://www.light2015.org/
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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?
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Physicists
Material scientists/engineers
Electrical engineers
Optical engineers
•
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SPIE (physicists/engineers)
APS (physicists)
OSA (physicists and engineers)
IEEE (engineers)
• NISE has contacts in SPIE and OSA
APS = American Physical Society, OSA = Optical Society of America,
IEEE = Institute of Electrical and Electronics Engineers
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Check-in Time
Any general questions about
the International Year of Light
or finding scientist partners?
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Light-related Resources from NISE
http://www.nisenet.org/events/other/in
ternational-year-light-2015
So many great resources!
NanoDays activities
Videos
Programs
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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
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Light-related Topics: Examples
• Light in nature
• Butterfly
• Thin Films
• Bubbles
http://www.nisenet.org/
• Nanoscale-phenomena
• Sunblock
• Nano Gold
• Invisibility
• New technologies/devices
• Liquid crystal displays
• Thin Films
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Light-Related Videos
Nano and Me - Gold
http://vimeo.com/31270439
http://www.nisenet.org/
What’s Nano About Bubbles?
http://vimeo.com/74400132
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Check-in Time
(1) Do you have a favorite light-related activity from NISE? If so,
what is it?
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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)?
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Absorption, Reflection, and Transmission
• 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
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Absorption, Reflection, and Transmission
Absorption + Reflection + Transmission = 100%
http://design.tutsplus.com/tutorials/draw-a-shiny-make-up-mirror-with-adobe-illustrator--vector-4418
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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
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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
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
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Nano Gold (Stained Glass)
http://design.tutsplus.com/tutorials/draw-a-shiny-make-up-mirror-with-adobe-illustrator--vector-4418
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Bulk vs Nano Gold
Bulk Gold
Stained glass
Nano Gold
http://education.mrsec.wisc.edu/nanolab/gold_uv/index.html#Introduction
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Size and Shape Matter
At the nanoscale,
size matters!
At the nanoscale,
shape matters, too!
http://www.horiba.com/scientific/
http://commons.wikimedia.org/wiki/File:Native_gold_nuggets.jpg
http://www.cat.gov.in/technology/laser/lpas/pps.html
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How are the Colors Created?
http://edcvs.co/130nfaU
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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
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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
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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
Example: translucent red cup
Red light
Reflected and
transmitted
Green light
Absorbed
Blue light
Absorbed
http://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
Example: Lycurgus cup
Red light
Transmitted
Green light
Absorbed and
scattered
Blue light
Absorbed and
scattered
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Applications of Nano Gold
https://vimeo.com/channels/nisenet/66928095
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UV Bracelets
http://design.tutsplus.com/tutorials/draw-a-shiny-make-up-mirror-with-adobe-illustrator--vector-4418
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UV Beads
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How UV Light Affects UV Beads
UV light
• 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
http://www.profbunsen.com.au/files/uvdetectionbeads.pdf
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UV Beads
Shine
UV light
Turn off UV light,
then wait
• 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
http://www.profbunsen.com.au/files/uvdetectionbeads.pdf
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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
http://chemwiki.ucdavis.edu/Wikitexts/Prince_George's_Community_College/General_Chemistry_for_Engineering/Unit_1%3A__Atomic_S
tructure/Chapter_2%3A_Atomic_Structure/Chapter_2.3%3A_Atomic_Spectra_and_Models_of_the_Atom
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UV Beads
Before UV exposure,
energy gaps are larger
Visible light doesn’t have
enough energy to promote
an electron
High energy
5 eV
Low energy
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UV Beads
Before UV exposure,
energy gaps are larger
After UV exposure, energy
gaps are smaller
Visible light doesn’t have
enough energy to promote
an electron
Certain colors of visible
light have enough energy
to promote electrons
High energy
[Orange bead]
5 eV
High energy
2.3 eV
Low energy
Low energy
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A New Invisibility Demo!
Just in time for IYL, there’s a new invisibility (cloaking) demo
you can try!
Exploring Properties - Invisibility
http://nisenet.org/catalog/programs/exploring_pro
perties_-_invisibility
Invisibility Cloak
http://nisenet.org/catalog/media/invisibility_cloak
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A New Invisibility Demo!
Just in time for IYL, there’s a new invisibility (cloaking) demo you can try!
http://www.rochester.edu/newscenter/
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The “Rochester Cloak”
4 lenses, with
some way to
hold them up
and align them
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The “Rochester Cloak”
http://www.rochester.edu/newscenter/
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The “Rochester Cloak”
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The “Rochester Cloak”
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The “Rochester Cloak”
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
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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-objectsacross-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
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Sunblock
http://design.tutsplus.com/tutorials/draw-a-shiny-make-up-mirror-with-adobe-illustrator--vector-4418
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Sunscreens vs Sunblocks
• Sunscreens use chemicals
• There are also sunblocks
that use minerals like zinc
oxide or titanium dioxide
nisenet.org vitaderminstitute.com/
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Sunscreens vs Sunblocks, Continued
How could sunscreen and sunblock work?
Sunscreen/Sunblock
Skin
Absorption
Sunscreen/Sunblock
Skin
Reflection
Sunscreen/Sunblock
Skin
Transmission
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Sunscreens vs Sunblocks, Continued
How could sunscreen and sunblock work?
Sunscreen/Sunblock
Skin
Absorption
Sunscreen/Sunblock
Sunscreen/Sunblock
Skin
Reflection
Skin
Transmission
Sunscreens and sunblocks both usually work through absorption of UV rays
Sunblocks are better because they absorb more of the UV rays
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Inorganic Sunblocks Absorb UV Better
ideal
UVB UVA
visible
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Nano Sunblocks
Traditional zinc oxide sun
blocks are very visible
http://www.tackletour.com/reviewbluelizard.html
Modern zinc oxide sun blocks are
fairly invisible after application
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Nano ZnO and TiO2 Reflect Less Light
UVB UVA
visible
ideal
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