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 Work
Katie was the first female scientist to work at the General
Electric Laboratory in Schenectady, New York. She was Dr. Irving
Langmuir's assistant. Katie and Langmuir worked on monomolecular
coatings designed to cover surfaces of water, metal, or glass. To
read about Katie's preparations for this job, go to biography.
Monomolecular means one molecule.
These special coatings that Katie worked on were oily and could be spread
in a thin layer on water, metal, or glass. To give you a better idea
of how thin these coatings were, 35,000 of these coatings stacked on top
of each other are only as thick as a piece of paper.
Inventions
Katie didn't discover what to do
with the coatings she had been working on until the 1930s. In 1938,
she figured out how to spread these monomolecular coatings one at a time
onto glass or metal. She used a barium stereate (a type of soap)
film to cover glass with 44 monomolecular coatings to create the first
"invisible" glass. Before this time, glass was distorted, difficult
to see through, and reflected
light. Even the most clear glass reflects 8-10% of light shining
on it: that is why glass is visible. Katie's invention made glass
less distored and more than 99% nonreflective. This coating is now
called the "Langmuir-Blodgett film." |
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THE PROCESS:
(remember: we can't do this on our
own-- Katie used special technology we don't have at home)
1. Put liquid soap on some water.
2. A thin film will form on the top.
3. Dip a plate of glass in the water and
pull it out again.
4. The film of soap will be on the glass.
5. Do this again 44 times.
6. The reflectiveness on the glass will become
only 1%. |
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In addition to inventing
"invisible" glass, Katie also invented the "color guage," which is a way
to measure the tiny molecular coatings on the glass to the nearest one
millionth of an inch. The "color guage" works on the idea that different
thicknesses of coatings are different colors. This example is most
easily observed when blowing soap bubbles, which are differently colored
because of varying thicknesses.
Before and after this invention that Katie
is best known for, she made other inventions as well. Katie wrote
a thesis on the absorption of gasses by carbon, which was later helpful
in the perfection of gas masks in World War I.
Katie also went on to make inventions
related to the World War II effort, inventing poison gas absorbents, methods
for de-icing aircraft wings, and improving smokescreens.
To learn how her inventions made the world
better, click on impact. |
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Why
Does This Work?
Glass is reflective, but not completely
reflective. We can see things because they reflect light. If
you look at something in the dark, it will be impossible to see it because
no light is reflecting off of it. Because we can see glass, we know
it is a little bit reflective (8-10% reflective.) Glass is mostly
see-through because it is not a solid. Glass is called "suspended
liquid." This means that it has the same properties as liquid, but
feels like a solid. Having the same properties of a liquid means
that the molecules in a pane of glass are far apart, allowing some light
to pass through.
Barium stearate is a soap-like, oily substance.
It is a liquid, and is also partially reflective. It is hard to understand,
but the structures of barium stereate molecules and glass molecules are
different in such a way that barium stereate's reflection of light will
precisely cancel out the reflection from the glass underneath.
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Awards
Katie receved patent #2,220,660 for the "Film Structure
and Method of Preparation" of "invisible glass." It was among the
6 patents that she obtained in her lifetime.
Here are some awards that she has received:
| 1939 |
Honorary Doctorate from Elmira College |
| 1942 |
Honorary Doctorate from Brown University |
| 1942 |
Honorary Doctorate from Western College |
| 1943 |
Starred in American Men of Science 1943 edition |
| 1944 |
Honorary Doctorate from Russell Sage College |
| 1945 |
American Association of University Women's Annual Achievement
Award |
| 1951 |
Francis Garvin Medal, American Chemical Society for work on
monomolecular films |
| 1951 |
Only scientist honored in Boston's First Assembly of American Women
in Achievement |
| 1951 |
Chosen by the U.S. Chamber of Commerce as one of the 15 "women
of achievement" |
| 1951 |
Schenectady honor of Katharine
Blodgett Day |
| 1972 |
Progress Medal of the Photographic Society of America |
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Publications
Here are articles that that Katie published about her inventions:
"Films Built by Depositing Successive Monomolecular Layers on a Solid
Surface," Journal of the American Chemical Society 57: 1007 (1935).
"Built-Up Films of Barium Stereate and Their Optical Properties,"
Physical Review 51: 964 (1937,) with Langmuir.
"Use of Interference to Extinquish Reflection of Light from Glass,"
Physical Review 55: 391 (1939).
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Time for a Quiz! Katie's
Inventions
Instructions: Decide on the correct answers
and fill out the whole quiz. Then click on the button at the bottom
to check your work.
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Wait, let me read it again
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Good Job! You are done with the
quiz.
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