At the end of January, I joined Caltech's chemistry club at Cleveland Elementary in Pasadena. Being at an elementary school, my audience seemed obvious: the younger half of the popular K-12 outreach target. I was eager—and nervous—to share chemistry with kids who probably had no idea what chemistry was, and I hoped to show them science as something fun, something magical.
Fortunately for me, being with the chemistry club meant that all of the preparation and outreach design had been taken care of. The group did the typical chemistry demonstrations: elephant's toothpaste, making silly putty from glue and borax, flame experiments showing that different chemicals give off different colorful flames, and demonstrations with liquid nitrogen. I was in charge of the liquid nitrogen part.
There are a couple of fun things you can do with liquid nitrogen, like make ice cream or flash-freeze a banana and use it to hammer in a nail (both of which are future demonstrations we hope to incorporate). I was giving three demonstrations of very cold things: flowers in liquid nitrogen, air-filled balloon in liquid nitrogen, and sublimation of dry ice to inflate a balloon (not a liquid nitrogen demonstration but still very cold!).
I opened up by asking the kids if they knew that, like very hot things can burn your skin, so can very cold things. After explaining frostbite, I showed them a vat of liquid nitrogen, so cold relative to room temperature, it gives off misty white vapors. I picked up a flower and plunged it into the liquid nitrogen, which began to boil since the flower was warm relative to the liquid. I then pulled out the flower and hit it against the table, and the students' eyes snapped open in shock as the petals shattered (just like in the demonstration in the video below).
After showing the frozen flowers, I took a balloon filled with air and asked the kids (and parents) what they thought would happen if I put it in liquid nitrogen. Most said that they thought it would pop, stepping back in case their hypotheses were correct; a few (several smiling cheekily because they had seen a similar demonstration before) guessed the balloon would deflate, which it did. I explained why, describing the slow-down of molecules at lower temperatures which then depressurized the balloon, causing it to collapse on itself. Pulling the balloon out of the vat, I showed that when the molecules in the balloon warmed back up, they began to collide again, building up pressure inside the balloon. I gave the analogy that when it is cold out, you just want to snuggle up on the sofa and drink hot chocolate while on warm, sunny days you want to run around outside and play. The parents were especially excited with this demonstration, and many asked to feel the balloon's platicy texture in response to their observations of the flowers in the prior demonstration.
By now, most of the kids' mouths were hanging open as I began my final display of the awesomeness of super cold things. I took some dry ice, which is solid carbon dioxide, and enclosed it in a balloon. As I began to shake it, I explained sublimation. While water ice—H2O ice—melts from a solid to a liquid, dry ice—CO2 ice—sublimates from a solid directly to a gas. As the energy of the CO2 molecules increased, the solid phase molecules began to sublime and the product gas began to inflate the balloon. Advising the kids not to touch the dry ice through the balloons, I handed them off to be carried around so the students could watch the balloons continue to inflate.
After showing these demonstrations several dozen times, I wasn't phased (science pun?) by the students' reactions: they were wide-eyed and surprised, before quickly turning to another demonstration in excitement and forgetting about the ones before. I was surprised, however, by the parents' reactions. Sure, I expect adults to have a longer attention span than children, but I didn't expect the adults to hang around and ask questions rather than hover over their children as they pranced off to make putty or see elephant toothpaste foam out of a volumetric flask. Nevertheless, the parents listened intently to my every word and asked questions. They asked what would happen if they substituted this material for that one or what liquid nitrogen is used for in industry. I realized just how important parents are in the learning process and in our efforts to promote science.
Teaching pedagogy emphasizes that students learn best through demonstrations when they predict the results beforehand and reflect on what actually happened after. This practice strengthens a student's understanding. Scientists often emphasize outreach to K-12 students as an important component of broader impacts as a result of their research. While I agree, I don't think that reaching out to students alone is effective. Sure, students will see how cool science is if you show them pretty flames, but they are easily distracted by other demonstrations, homework, gossip, and a nearly infinite list of things happening in their lives. Students often don't have the time or aren't motivated to reflect on their own. Heck, I've been a student for nearly 21 years and I still have trouble doing this.
By including parents in our outreach and encouraging parents to ask questions and get excited about science, we indirectly encourage students to reflect on what they saw. I think that we think of K-12 students as the group most impressionable when it comes to science demonstrations because their interests are maturing rapidly, and that may be true in the short term, but just because the time has passed for an adult to grow up wanting to be a scientist doesn't mean they aren't excited by science. If outreach is targeted to K-12 parents as well as their guardians, perhaps losing students' attention won't equate with a lost opportunity for reflection. Instead, parents who are engaged in outreach might ask their child in the car on the way home what they thought about a demonstration, what surprised them, what frustrated them, what they liked, what they didn't care for.
Moreover, reflection wouldn't be reserved to immediately after an exhibition of science. If a parent tunes into boiling water being mixed with liquid nitrogen to create a billowing cloud of gas, the next time it rains they might explain cold and warm fronts colliding and refer back to the demonstration that made their child jump up and down in awe. By making these connections—something children often cannot do because they are novices—guardians can increase their child's understanding hence interesting in a topic such as meteorology as well as science generally.
While assemblies are great (what kid doesn't love getting out of class for an hour or so?), they potentially cut out perhaps the most important learning tool: reflection. Relying on the teachers is unfair and unrealistic; they have their own curricula to get through. Plus, they (hopefully) are already excited about the subject. By getting parents excited too, I think inspiration by science can trickle down more effectively. Hence targeting adults, not just children, in science outreach should be a priority for scientists when engaging the public.
Do you have other ideas for increasing engagement in outreach? Share them in the comments!