Transcript Nanotechnology - Hinsdale Township High School District 86

Nanotechnology in the High
School Curriculum: From
Energy Conversion to Science
Ethics
REU (RET) Nanotechnology Symposium
23 July 2004
12-2:30 PM
Kenneth Bowles
Apopka High School
NSF: NANOPAC REU Site
Host: AMPAC-UCF
nanomachines
What Is All the Fuss About
Nanotechnology?
Any given search engine will
produce 1.6 million hits
Nanotechnology is on the way to
becoming the FIRST trillion dollar
market
Nanotechnology influences almost
every facet of every day life such as
security and medicine.
Does Nanotechnology
Address Teaching Standards?
Physical science content standards 9-12
• Structure of atoms
• Structure and properties of matter
• Chemical reactions
• Motion and forces
• Conservation of energy and increase in disorder
(entropy)
• Interactions of energy and matter
Does Nanotechnology
Address Teaching Standards?
Science and technology standards
• Abilities of technological design
• Understanding about science and technology
Science in personal and social perspectives
• Personal and community health
• Population growth
• Natural resources
• Environmental quality
• Natural and human-induced hazards
• Science and technology in local, national, and
global challenges
Does Nanotechnology
Address Teaching Standards?
History and nature of science
standards
• Science as a human endeavor
• Nature of scientific knowledge
• Historical perspective
Does Nanotechnology
Address Teaching Standards?
i
Nanotechnology Idea
Standard it can address
The idea of “Nano” – being small
Structure of Atoms
Nanomaterials have a high
surface area
(nanosensors for toxins)
Structure and properties of
matter, Personal and Community
Health
Synthesis of nanomaterials and
support chemistry (space propulsion)
Chemical Reactions
Shape Memory Alloys
Motion and Forces, Abilities of
technological design, Understanding
about science and technology
Nanocrystalline Solar Cells
Conservation of Energy and increase
in disorder (entropy), Interactions of
energy and matter, Natural Resources
Nanocoatings resistive to bacteria and Personal and Community Health,
pollution
Population Growth, Environmental
Quality, Natural and human-induced
hazards
Does Nanotechnology Address
Teaching Standards?
Nanotechnology Idea
Standard it can address
Nanomaterials, such as MR
(magneto-resistive) fluids in security
Science and technology in local,
national, and global challenges
Richard P. Feynman’s talk, “There is
plenty of room at the bottom”.
Feynman had a vision.
Science as a human endeavor,
Nature of scientific knowledge,
Historical perspective
Nanocosmetics and nanoclothing
Science as a human endeavor,
Science and technology in local,
national, and global challenges
Nanotechnology and Science Ethics
Science and technology in local,
national, and global challenges,
Science as a human endeavor,
Historical perspective, Natural and
human-induced hazards, Population
Growth, Personal and Community
Health
An Example of a Nanotechnology
Experiment, Which Addresses
the Standards: Constructing
Nanocrystalline Solar Cells Using
the Dye Extracted From Citrus
Four main parts:
1. Nanolayer
2. Dye
3. Electrolyte
4. 2 electrodes
Nanocrystalline Solar Cells: The
Materials:
Materials
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
(2) F-SnO2glass
slides
Iodine and Potassium
Iodide
Mortar/Pestle
Air Gun
Surfactant (Triton X
100 or Detergent)
Colloidal Titanium
Dioxide Powder
Nitric Acid
Blackberries,
raspberries, green
citrus leaves etc.
Masking Tape
Tweezers
Filter paper
Binder Clips
Various glassware
Multi-meter
Preparation of Nanotitanium and
Electrolyte Solution
Nanotitanium
1.
2.
3.
4.
5.
Add 2-ml of 2,4 – Pentanedione (C5H8O2) to 100-ml of
anhydrous isopropanol [ (CH3)2CHOH ] and stir covered for
20 minutes.
Add 6.04-ml of titanium isopropoxide (Ti[(CH3)2CHO]4 to the
solution and stir for at least 2 hours.
Add 2.88-ml of distilled water and stir for another 2 hours.
The solution must then age for 12 hours at room
temperature.
Since you now have a collodial suspension, the solvent
must be evaporated off in an oven to collect the powder.
Electrolyte solution
1.
2.
3.
4.
Measure out 10-ml of ethylene glycol
Weigh out 0.127-g of I2 and add it to the ethylene glycol
and stir.
Weigh out 0.83 g of KI and add it to the same ethylene
glycol.
Stir and sore in a dark container with a tight lid.
Nanocrystalline Solar Cells
Main component:
Fluorine doped tin
oxide conductive
glass slides
Test the slide with a
multimeter to
determine which side
is conductive
Synthesis of the
Nanotitanium Suspension
Procedure:
• Add 9 ml (in 1 ml increments) of
nitric or acetic acid (ph3-4) to
six grams of titanium dioxide in
a mortar and pestle.
• Grinding for 30 minutes will
produce a lump free paste.
• 1 drop of a surfactant is then
added ( triton X 100 or dish
washing detergent).
• Suspension is then stored and
allow to equilibrate for 15
minutes.
Coating the Cell
• After testing to determine
which side is conductive,
one of the glass slides is
then masked off 1-2 mm on
THREE sides with masking
tape. This is to form a mold.
• A couple of drops if the
titanium dioxide suspension
is then added and distributed
across the area of the mold
with a glass rod.
• The slide is then set aside to
dry for one minute.
Calcination of the Solar
Cells
• After the first slide has dried the
tape can be removed.
• The titanium dioxide layer needs
to be heat sintered and this can
be done by using a hot air gun
that can reach a temperature of at
least 450 degrees Celsius.
• This heating process should last
30 minutes.
Dye Preparation
• Crush 5-6 fresh berries in a mortar and pestle
with 2-ml of de-ionized water.
• The dye is then filter through tissue or a
coffee filter and collected.
• As an optional method, the dye can be
purified by crushing only 2-3 berries and
adding 10-ml of methanol/acetic acid/water
(25:4:21 by volume)
Dye Absorption and Coating
the Counter Electrode
• Allow the heat sintered slide to
cool to room temperature.
• Once the slide has cooled,
place the slide face down in the
filtered dye and allow the dye to
be absorbed for 5 or more
minutes.
•While the first slide is soaking,
determine which side of the second
slide is conducting.
•Place the second slide over an open
flame and move back and forth.
•This will coat the second slide with a
carbon catalyst layer
Assembling the Solar Cell
• After the first slide had
absorbed the dye, it is
quickly rinsed with ethanol to
remove any water. It is then
blotted dry with tissue paper.
• Quickly, the two slides are
placed in an offset manner
together so that the layers
are touching.
• Binder clips can be used to
keep the two slides together.
•One drop of a liquid
iodide/iodine solution is
then added between the
slides. Capillary action will
stain the entire inside of
the slides
How Does All This Work?
1.
2.
3.
The dye absorbs
light and transfers
excited electrons
to the TiO2.
The electron is
quickly replaced
by the electrolyte
added.
The electrolyte in
turns obtains an
electron from the
catalyst coated
counter electrode.
TiO2=electron acceptor; Iodide = electron donor;
Dye = photochemical pump
Classroom Ideas With the Cell
• Ohm’s law
• Electrochemistry
• Verification of Kirchhoff’s voltage law with
cells in series.
• Charging capacitors
• Measuring current and power density
• Measuring internal resistance
• Powering small “no-load” motors
Using the Cell to Measure the
Time Constant for an RC Circuit
Materials: solar
cell, Logger Pro,
Graphical
Analysis for
Windows, Vernier
LabPro,
Voltage/Current
probe, Pasco RC
Circuit Board
Using the Cell to Measure the
Time Constant for an RC
Circuit
Capacitor Basics:
V(t) = terminal voltage, e = EMF ( maximum voltage) , t =
time, R = resistance(15KW), C = capacitance(1000mF)
t = time constant = RC =(15x103)(1000x10-6)=15 seconds
Equation for discharging a
Capacitor
Using the Cell to Measure the
Time Constant for an RC Circuit
Re-arranging the equation algebraically to represent the
slope formula.
What this basically says is that if you plot the natural log of the
ratio of potentials versus the time the slope will equal the inverse
of the time constant for this particular RC circuit.
Using the Cell to Measure the
Time Constant for an RC Circuit
The capacitor was first
fully charged then
allowed to discharge.
The EMF was
determine to be
The voltage at t=0.
Using the examine function we
can get various voltage and time
data points from the graph.
The natural log function can then
be applied mathematically.
Using the Cell to Measure the
Time Constant for an RC Circuit
For a normal 1.5
V battery
For the solar cell
Using the Cell to Measure the
Time Constant for an RC Circuit
For the solar cell
For the battery
Conclusion:
The nanocrystalline solar cell
could easily be used in a
physics classroom to study
capacitors as well as
introduce the idea of
harnessing the sun’s energy
using nanotechnology.
Nanotechnology
Curriculum Overview
Summary of teaching modules in a
Teacher’s Guide for nanotechnology
•
Measurement activity called
measuring the visible understanding
the invisible
•
Understanding surface area kinetics
•
Electrical applications of solar cells
•
Reading in nanotechnology
•
15 week science ethics forum
Nanotechnology Curriculum
Overview - Reading
Apopka oasis reading
café
• Michael Crichton’s
“prey”
• John Robert
Marlow’s “Nano”
Nanotechnology Curriculum
Overview - Reading
Each activity is accompanied by a nanotechnology article
which includes:
• Pre-reading activities such as an anticipation guide
• Reading strategies such as questioning and prediction verification
• Post reading strategies such as the “One Sentence Summary.
Nanotechnology
and Science
Ethics
Based on a course
offered at Yale
Week
Overview (Feynman’s “There is plenty of room at the
bottom”)
2. From Fenyman to Funding: The Mighty Dollar
3. Super intelligence
4. Nanotechnology
5. Life Extension and Cryonics
6. Pharmaceutical Enrichment ( Brave New World)
7. Threats to Global Security
8. Strategies for Global Security ( I,Robot)
9. Automation
10. Enhanced humans and Immortality
11. Environmental Effects of nanotechnology
12. The Gap between science and ethics.
1.
Planned Nanotechnology
Activities
Activities:
1. Making magnetic tiles to simulate “self assembly”.
2. Making Ferro Fluids to simulate the manufacture
of projectile repellant materials.
3. Using Decanethiol Monolayer on Silver to simulate
nanoparticles that resist stains and water
absorbance.
4. A Microfluidic Nanofilter: Filtration of Gold
Nanoparticles to simulate nanosensors.
5. Residual Stress on Nanolayers due to Thermal
Heating
6. Various Shape Memory Alloy Experiments
7. Various Nanocoating experiments using bacteria
Special Thanks
Dr. Sudipta Seal- Nano Initiative Coordinator for
UCF – NSF REU(RET) Site Funding
Dr. Kumar and Dr. Peterson – UCF Mechanical,
Materials & Aerospace Engineering –NSF RET Site
Funding
Dr. Aldrin Sweeney – UCF College of Education
AMPAC
Karen Glidewell - AMPAC Administrative Offices
For More Information
Please visit:
www.bowlesphysics.com
• Download this presentation
• Download Teaching Modules