Bond. Ionic Bond. Holiday Science Lecture with PCCM.

by lianz


By: Lian Zhu 

Some days when the days get dark way too early, when you’ve just had it with microscopes and genetically modifying C. elegans, it’s nice to hang out with people who find science cool, namely kids under the age of 12. Even cooler is when you can call it volunteering and get a nifty science shirt and breakfast/lunch out of the whole deal.  This is exactly what happened last Saturday when I volunteered (or rather shoved shirts with science puns at excited children) at the Annual Holiday Science Lecture hosted by PCCM and organized by Dan Steinberg, Howard Stone, and Bonnie Bassler from PCCM/PRISM.  The maestro, Prof. Howard Stone, who probably never had to use a clapping technique in order to get graduate students to pay attention in one of his classes before, gave the lecture while being assisted by Prof. Bonnie Bassler.  This year the topic was “A grain of salt: isn’t it ionic?”  Below is a play by play of my Saturday hanging out with these future scientists-to-be and their parents (some of which were already scientists).


9:15am – Report for duty, wear green t-shirt with delightful pun.  Eat a bagel with cream cheese, drink OJ, hang out with the other volunteers, play around with the LED light and battery that the kids are going to use for their demo.  Also re-introduce myself to Howard, but this time it definitely stuck.

9:30am – Parents and their budding scientists begin arriving.  I’m manning the t-shirt table, where kids get to pick a t-shirt out of the options of Na+, Cl-, H2O, and Ag+, the participatory elements and molecule that will be a part of the reactions described during the lecture.  While we t-shirt handers expound on the uniqueness of Cl- (being the only negative ion), or the interesting physical properties of Ag+, or the hilarity of the “may the intramolecular forces be with you” on the H2O, the kids I’m sure were much more focused on the practical problem of “I LIKE BLUE” or “noooo… I want an ORANGE shirt.”  When I told one kid that Cl- would have the choice to either precipitate with Ag+ OR Na+, the kid very poignantly notified me that he felt “meh” about the yellow. 

9:45am – Discover where kids are preoccupied with the color, parents were more preoccupied rightly with the shirt size.   Although I particularly appreciated the parents who wanted one offspring to be Na+ and the other to be Cl-.  The blue water shirt was by far the most popular.

10:00am – All kids were herded inside and the lecture started.  Howard started with  description of ions and a neat demo about dissolution of salt vs. sugar.  The class made predictions of HolidayLecture1which one would be more soluble at higher temps.  The power of suggestion was very high in that most people picked salt since the name of the lecture centered on it.  A water molecule and a salt ion (and their enthusiastic parents) led the demonstration.   

10:14am (Roughly, really these times are just for effect) – The water molecules and sodium and chloride ions flooded the stage to demonstrate how dissolution of a sodium chloride lattice occurs.  The water molecules exhibited knowledge of the existence of their dipole by shaking their right hand (negative dipole) when recruiting a positive sodium ion and their left (positive dipole) when recruiting the negative chloride ion.  It was actually pretty beautiful watching a lattice of orange and yellow dissolve with a flood of enthusiastic blue water molecules.

lecture_pic10:20am – The ions take their seats and the lecture resumes with talk and a demo of precipitation of AgCl, the opposition of the dissolution.  And this time water and the silver and chloride ions take the stage, the chloride ions drift around in a sea of water until a crowd of silver rushes in and pulls chloride ions out to the side, many new friends were surely made in the process.   Howard presents a medical mystery about how water was once tested for the presence of cholera by John Snow via their salt content by a similar experiment (adding AgNO3 to precipitate out AgCl).  In this case the precipitate was very much a part of the solution. 



10:30am – The absorbent polymer commonly found in diapers was mixed with water and was attempted to be dumped on Bonnie’s head, but didn’t come out to the disappointed of the chaos loving crowd.  Salt was added, which dissolved the polymer mixture, and Bonnie found a bucket in the nick of time.

10:lightsaber45am – Dan lead the kids in their very own conductivity experiments using and LED light, a small battery, a paper towel, some water, salt, and a straw.  The kids saw the LED bulb light up, saw that having a paper towel in between stalled the conductivity, and that salt water on the paper towel remedied this by conducting electricity through the ions.  Most kids participated, and all kids made a light saber by taping the battery led to one end of the straw.  The force was definitely strong in the room as a bunch of green and red light sabers were waved around the room.

10:50am – The show ended with a really cool demonstration of osmosis of red blood cells live, showing that red blood cells inflated from their sickle shape once distilled water was added to the system since the amount of salt inside the cells were higher than their surrounding, and they wanted to equalize this misbalance of osmotic pressure.  Howard flexed his comedic timing by pretending Bonnie’s blood sample contained our friendly neighborhood C. elegans.

11:00am – The show ended, the kids headed out waving their lightsabers, and the volunteers grabbed lunch and pillaged last year’s DNA t-shirts that rocked phrases like “just hanging with thymine”.

11:45am – Ran to lab to do something with tissue culture

12:15am – Repeat. Admitted to myself that it's perhaps these small moments of humanity that can lend such an unique beauty to science.  Perhaps it's these moments of witnessing people's first interaction with a concept that reminds you of how amazing and beautiful all these concepts really are, how the work of entire scientific communities can be taught in an hour with t-shirts and LEDs to wide-eyed, color loving, youths.

For more information on the Holiday Science Lecture and other programming, check out and

Lian Zhu is currenlianzhupictly a third year graduate student in Chemical and Biological Engineering.  She studies the biophysical assembly and function of the nucleolus in the cell in the Brangwynne Lab and is generally interested in science, particularly its communication and infrastructure.  When she's not hanging out with c. elegans or tissue culture cells, she practices with the Princeton Tae Kwon Do team, messes around with poetry and the cello, hikes, and learns new languages.  She loves the poetry of Jorge Luis Borges and randomly encountering the Latin language and curious people.  She hopes to explore intersections between art and science or just intersections in our voyage as humans on this blog.  Please feel free to contact her at with any ideas and comments!

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