49 - Grab Bag IV (w/ Adele Musicant!)
49. Grab Bag IV
Some topics are short and sweet, but do not warrant an entire episode of conversation. There have been many requests for smaller topics to be discussed: thusly, establishment of the grab bag is a proper solution. Today we’ll discuss dry ice; women’s representation in film; and science communication to allow us to be scientifically conversational.
LEARN MORE ABOUT TRUTALKS!
TRUtalks is a science communication & outreach series that aims to make science accessible to the public. Once a month, at TRU Deli & Wine Bar in Chapel Hill, we host a scientist who discusses their research in a ~20 minute talk to a general audience. We then open it up for an extended Q&A session to encourage public interaction with real scientists! We try to assume only a high school-level science education so that talks can be understood by scientists and non-scientists alike. It is our belief that science is too often communicated only to a PhD-level audience. In this era of public misinterpretation and general mistrust of science, it is incredibly important to bring current scientific findings to a wider audience.
TRUtalks is on Twitter (@TruSciTalks) and on Facebook (https://www.facebook.com/groups/1006525769435603/). We also have a mailing list (http://eepurl.com/grClUL).
General Learning Concepts
1) Dry Ice
a. What is dry ice? Dry ice is the name for carbon dioxide in its solid state.
b. Why is dry ice cold? The temperature of the surface of a block of solid carbon dioxide (dry ice) is -78.5 degrees C (-109.8 degrees F). Carbon dioxide freezes at a lower temperature: -79 degrees Celsius or -109 degrees Fahrenheit! Because of its intrinsic physical processes (see phase diagram), carbon dioxide forms a solid and not a liquid at standard pressures. Still, dry ice is often made from liquid CO2 (which has been pressured and cooled).
c. Why does dry ice produce the gas I know and love? At room temperature, it will go from a solid to a gas directly (sublimation). While carbon dioxide gas is invisible, the very cold gas causes water vapor in the air to condense into water droplets, thus creating fog.
d. Fun tidbit: See reference
2) Bechdel Test
a. What is the Bechdel test? The test is named for Alison Bechdel, an illustrator who, in 1985, presented the rule in an installment of her “Dykes to Watch Out For” comic strip. The Bechdel test is not supposed to be an endorsement of a particular film that passes it, nor an indictment of a particular film that fails it. Still, the Bechdel Test remains useful for how little it asks of movies, and for the sobering fact that many films still fail to meet its basic criteria.
i. Does the movie contain two or more (named) female characters?
ii. Do those characters talk to each other?
iii. If so, do they discuss something other than a man?
b. Statistics of the Bechdel test: See reference.
c. What is the next Bechdel test? A 538 article made mention of 12 new tests (designed from female writers, actors, directors, producers) who want films to have more women working for production, more leadership roles, more diverse representation of women, more educated women, and women in more pivotal roles within film.
3) Bioluminescence
a. What is bioluminescence? The production and emission of light by a living organism. Think of the glowing of a firefly, jellyfish, or angler fish.
b. How does bioluminescence occur? Bioluminescence occurs as the result of an enzymatic reaction where the luciferase enzyme acts on a starting material like luciferin to produce several reaction products, one of which is light. People observed this phenomenon as early as 1500-1000 BCE but the components of the reaction weren’t truly understood until the 1900s.
c. What is bioluminescence used for? In animals, bioluminescence serves a variety of functions. Fireflies pulse bioluminescent signals at each other to signal to potential mates. Some aquatic organisms use bioluminescence as camouflage or as defense (think of an organism ejecting a bioluminescent substance much the same way a squid might eject ink). Other animals, like the angler fish, use it to lure in prey. Scientists now exploit bioluminescence for biological studies. For example, in my lab, we use bioluminescence to track tumors. We have engineered an extremely bright bioluminescent reporter and we express this in our cancer cells. Then, we can track tumor growth over time simply by injecting the luciferase substrate into our mice and capturing the resultant light output.