Every year since 2008, NSF has carried out a nationwide festival of educational programs focusing on nanoscale science known as “NanoDays”, and 2013 was no exception. The event took place on April 14th, 2013 at the Mayagüez Mall in Mayagüez, Puerto Rico, where the local community, especially K-12 students, witnessed several activities and experiments/demonstrations on such topics as ferrofluids, catalysis, nanobiotechnology, and nanoscience in general. The experiments and demonstrations were presented by numerous research groups with different backgrounds from the University of Puerto Rico in Mayagüez. The local event was made possible thanks to the collaborations of Wi(PR)2EM project and Science on Wheels.
Our research group was present with a number of hands-on experiences to explain two key physical phenomena observed at nanoscales: Brownian motion and inertialess particle dynamics. First, the visiting public was introduced to the notion of nanoscales. They were asked how small they though a nanometer was. After a few responses from the public, we explained its size in terms of factors of 1000. We began by showing a meter stick, and then they were told that millimeters are obtained by dividing the meter into a 1000 pieces of equal length. The explanation continued the same way until Nano scale was reached. Then we moved on to the demonstration.
The “Brownian motion” demonstration consisted of a small box with marbles representing fluid molecules around a disk or the colloidal particle. Visitors had the opportunity to interact with this experiment by pushing the “molecules” into the “colloid” and causing random displacement. Also, they had the opportunity to observe the actual Brownian motion of a suspension of silica particles under the microscope. Additionally, a video of the same suspension (taken in the lab) was presented in case the observers could not appreciate the Brownian motion due to the vibrations of the table or sedimentation of the particles.
After the Brownian motion demonstration was finished, we continued the activity with an explanation of the effects of viscosity in particle dynamics at different length scales. For such purpose we explained the concept of viscosity using corn syrup and water. Visitors observed and compared the flowing capabilities of both fluids contained in jars by shaking them. Then, we discussed its effect on particle dynamics by conducting an experiment consisting of a swimming pull-string toy (duck) submerged in corn syrup. Visitors pulled the string on the toy and watched how the toy struggled to move on the fluid, but didn’t achieve a significant displacement. The size and viscosity dependence of the propulsion efficiency was also explained with the aid of the classic educational video from G.I. Taylor in Low Reynolds Number Flows (“Self-propelling bodies” section, See Part 3 (7:30-8:40)). This video shows that propulsion mechanisms at large scale are inefficient at nanoscale due to the kinematic reversibility of the fluids at this scale.
This year’s event featured the collaboration of 88 graduate and undergraduate students, 1 high school teacher, 5 high school students, 1 elementary school student and 4 professors with over 3,500 visitors to the stations. A total of 533 participants were surveyed on their age, educational background and different aspects of the event (e.g. organization, clarity of demonstrations, explanation of concepts, etc.). In summary, 14% of our visitors were elementary school students, 22% were middle or high school students and 33% were between 35 and 60 years old. All of the surveyed visitors stated that they clearly understood the concepts and demonstrations presented at the stations and that the activity was well organized.
These statistics show an overall improvement of the activity as compared to last year’s, not only in the quantity of visitors but also in the their satisfaction as well as in the organization of the event. This is the outcome after all of the collaborators’ hard work, dedication and commitment towards the promotion of, not only nanotechnology, but STEM fields in general. The success of these types of events motivates us to continue with the efforts of providing young students with enriching experiences that may encourage them to pursue careers in Science as well as to improve STEM education nationwide.
UCF Research Group Participants: Ubaldo M Córdova-Figueroa, Luis Y. Rivera-Rivera, Ronal A. De La Cruz-Araujo