Post on 23-Dec-2015
NANOTECHNOLOGY IN SECONDARY SCIENCE CLASSROOM: MODELING A
GAS SENSOR
Elena Cox, Ph. D.,Curriculum & Instruction,
Texas A&M University, CommerceThe 7th Annual Texas STEM Conference
DallasFebruary 6, 2014
Introduction
Research Experience for Teachers (RET) program at Georgia Institute of Technology
Research team at Mechanical Engineering worked with developing and designing microelectromechanical gas sensors
Clean room
• Air
• Clothing
• Rules of behavior and safety
• Introduction to the latest equipment and advances in science and technology available in the area of nanotechnology.
Microelectronic Fabrication Micro gas sensors are fabricated on silicon
wafers which I saw there for the first time.
Microelectronic Fabrication
One thing is to see the pictures of computer chips in textbooks, and another thing is to actually to learn how to make them yourself.
Microelectronic Fabrication
The professor in charge of the research team has more than 200 patents and supervises a research group of graduate students, always found the time to introduce me to microelectronic fabrication and to teach me how to work with silicon wafers.
Basics of Photolithography
Most of the time during the Summer RET program was spent learning about and working with nano photolithography
Basics of Photolithography
As a part of research team, I was allowed to work in a clean room performing the following operations:
Spinning of photoresist:
Basics of Photolithography
Aligning the mask:
Basics of Photolithography
Developing photoresist:
Basics of Photolithography
The pattern quality check by using profilometer and a microscope:
Basics of Photolithography
Chemical and plasma etching
Basics of Photolithography
Cutting the wafer and glass bonding:
Basics of Photolithography
All this work was required to manufacture a gas chromatographic column less than 1/3 of an inch but 2 meters long.
Chemistry TEKs
(4) Science concepts. The student knows the characteristics of matter and can analyze the relationships between chemical and physical changes and properties. The student is expected to:(D) classify matter as pure substances or mixtures through investigation of their properties.
Gas Chromatograph: Separation of Mixtures
http://en.wikipedia.org/wiki/Gas_chromatography
Gas Chromatograph
Macro-scale Gas Chromatographic Column
Gas Chromatographer Video
Miniaturized Gas Chromatographic Column on Silicon Wafer
2 cm
SEM of a DRIE etched silicon microchannel of GC.
Noh et al., 2002
SEM images of a parylene-coated silicon microchannel.
Noh, 2004
Column geometry. Parylene column (middle) and parylene
column with heat diffuser (right)
Noh et al., 2002
Introducing Nanotechnology by Modeling the Gas Sensor
I could talk to students about the properties of atoms in more detail because I was working with structures on atomic level.
I was able to develop a lesson plan and conduct a lesson based on the knowledge I gained during RET on chromatography pertaining in a separation of mixtures unit.
Chromatography Concept and Chemistry TEK 4d
The chromatography lesson was presented at teacher conferences in Washington and San Francisco.
Modeling Gas Nano-Sensor at Texas A&M University: Project-Based Learning in STEM
classroom
Modeling Gas Nano-Sensor at Texas A&M University: Project-Based Learning in STEM
classroom
Modeling Gas Nano-Sensor at Texas A&M University: Project-Based Learning in STEM
classroom
Modeling Gas Nano-Sensor at Texas A&M University: Project-Based Learning in STEM
classroom
CANDY CHROMATOGRAPHY: MODELING A GAS SENSOR
In your bag:• small bowl• coffee filters • droppers • Plate • 2 Clear drinking glasses filled with water• Drinking glass filled with salt water • Skittles, Gobstoppers, M&M's Ruler • Pencil• Food colors• Silica gel
Food Colors Separation
Put silica gel into one of the clear glasses filled with water. Wait for about 1 minute for crystals to absorb water.
Food Colors Separation
Put silica gel into one of the clear glasses filled with water. Wait for about 1 minute for crystals to absorb water.
Using dropper, put several drops of food color mixture on the silica gel after it increase in size.
Food Colors Separation
Put silica gel into one of the clear glasses filled with water. Wait for about 1 minute for crystals to absorb water.
Using dropper, put several drops of food color mixture on the silica gel after it increase in size.
Pour some water over the silica gel/the drops.
Food Color Separation
Food Color Separation
What do you observe? What food colors were mixed?
Food Color Chromatography
Take the unused tall clear glass filled with water covering the bottom of the glass.
Food Color Chromatography
Take the unused tall clear glass filled with water covering the bottom of the glass.
Take a strip of filter paper. Roll it over the Q-tip
Food Color Chromatography
Take the unused tall clear glass filled with water covering the bottom of the glass.
Take a strip of filter paper. Roll it over the Q-tip
Using a pencil and a ruler, draw the line about ¼” from the edge of the paper
Mark a dot where you will put your separation mixture with a pencil
Food Color Chromatography
Take the unused tall clear glass filled with water covering the bottom of the glass.
Take a strip of filter paper. Roll it over the Q-tip
Using a pencil and a ruler, draw the line about ¼” from the edge of the paper
Mark a dot where you will put your separation mixture with a pencil
Food Color Chromatography
Using a dropper, put one drop of a food color mixture on the dot on the filter paper
Food Color Chromatography
Carefully place the Q-tip with filter paper inside your glass with water.
Wait for the water to start rising on the filter paper.
Food Color Cromatography
Food Color Chromatography
What changes of your dot do you observe?
What colors do you think were mixed together? Can you tell the difference between colors?
Candy Chromatography Take out a dinner plate and lay one of
each color of Skittles, leaving a little space around each one.
Using a pipette or dropper, squeeze a little water onto each piece of candy to start dissolving the shell.
While you wait for the candy to dissolve, draw a pencil line about 2 cm from the bottom edge of the paper. Do not use pen, because the ink will run. This is your origin line.
When the water around the candy has turned color, squeeze the colored water into the pipette bulb.
Drop a few drops of colored water on the origin line on your filter paper. You may need to add several drops to ensure you have enough dye.
Repeat this with each color, leaving about 2 cm between each color
Let the filter paper dry completely.
Place filter paper in the glass with salt water so that it is standing up and the bottom is barely touching the surface of the salt solution.
You can tape the top of the filter paper to a pencil and hang it down into the solution if you have a hard time getting it to stay right at the surface.
Observe the salt water rising up the paper by capillary action until it is almost at the top.
Remove the paper from the glass and mark with a pencil where the solvent stopped.
Let the paper dry completely.
Repeat the experiment using M&M's, Gobstoppers or other dyed candy and compare like colors. Is the red dye the same in all of the candies, or do the colors run differently?