Science is too interesting to keep it cloistered in the classroom! For almost 30 years, we have been sharing the wonders of nature with others in our school through the use of display cases and exhibits located outside the classroom. While doing science in the hallway or other non-traditional settings may seem a bit unorthodox, this form of informal education beckons members of the entire school community to learn just how interesting and enjoyable science can be.
Science displays are always a favorite of parents attending a school’s open house. Adults are always interested in seeing what goes on in their son or daughter’s school, and science displays provide one window into the school’s academic program. Parents often comment that the science displays are the highlight of the open house.
Our first involvement in hallway science displays occurred when we realized that the primary use of our school’s display cases was to store and display trophies. Many cases were not used at all. It occurred to us that we might be able to use these showcases as extensions of the classroom. Our very first effort revealed that a science showcase attracts both science students and non-students alike. In fact, we learned that the display case is an excellent way of introducing non-science students to the wonders of the various scientific disciplines. Students often spend their passing periods trying to understand some phenomenon that to them seems paradoxical or a violation of common sense.
Interactivity is the key to a good display. Doing, not just looking and reading, engages both hands and minds. Furthermore, the more open-ended an activity, the better. Individuals should be able to view the apparatus as a vehicle of discovery and feel free to ask, “what will happen if I do this or that.” As you’ll see, even displays behind glass can be interactive.
The following examples of hallway exhibits and display cases have been very popular with our students. While inexpensive and simple to build and use, they have provided hundreds of students of all ages with a great deal of pleasure and perhaps a desire to learn more about the wonderful world in which they live. Hopefully, these exhibits will get you thinking about ways of decking your halls with science!
Polarization Tape Art
Some transparent tapes separate white light into its component colors when sandwiched between two polarizing filters. Using clear packing tape and a pair of polarizing filters, your students can create beautiful colored designs reminiscent of cubist art and stained glass windows.
The colors produced depend on the thickness of the tape. Tape is cut into desired shapes and layered on a transparent substrate such as a blank overhead transparency. By varying the number of tape layers in each region, a full palate of color is available to the budding Picassos.
In a recent display case, student-produced tape designs were displayed on a light table borrowed from the art department. The tape art was placed on a sheet of polarizing film that covered the stage of the light table. When visitors viewed the artwork through a hand-held Polaroid filter (available outside the display case, loose or tethered with string) brilliant colors were observed. Rotating the polarizing filter produced dramatic changes in the observed colors. Oohs and aahs were frequently heard coming from passers by who stopped to view the display.
Making polarization tape art may be used as a culminating activity after studying light and color in physics class or as an inter-disciplinary project. For example, we brought physics and art students together for a week so that the “two cultures” could gain both a knowledge and appreciation of what are usually considered to be disparate disciplines. Sharing the finished artwork through a hallway exhibit allows all to enjoy the marriage of art and science.
Visual Perception and Illusions
The possibilities for designing a display case on visual perception are endless! Perhaps the simplest approach is to use printed illusions. Figures and photos of visual illusions found in books may be photocopied. Engaging posters may be purchased in both shops and on the Internet. Suggestions for viewing the images along with brief explanations of the illusions are recommended. While not physically interactive, a display of illusory images has the power to engage and amaze.
Simple three-dimensional exhibits may also be incorporated into the illusion display case. A collection of reverse masks makes for a great display! We are accustomed to seeing convex faces so it is not surprising that when presented with a concave face, we unconsciously see what we expect to see.
The reverse Einstein mask certainly appears to be in relief even though it’s not. But there’s more! When you walk by the face, it appears to follow you. A simple yet effective reverse mask results from viewing the concave side of an inexpensive plastic mask. The effect is often best if the mask is white. Filling a display case with a number of these masks makes for a most eerie exhibit!
Pipes of Pan
A trip to the carpet store was the genesis of the giant ambient noise resonators or Pipes of Pan, as they are sometimes called. Eight carpet tubes mounted on a plywood base became the basis for a rather strange musical instrument. Based on the principle of resonance, the air in each tube vibrates with a frequency determined by the length of the tube. The background noise in a room contains virtually all audible frequencies, and is capable of creating resonant vibrations in each of the tubes.
We simply put our Pipes of Pan in our school’s central hallway and allow people to explore. A sheet with suggestions for use and a brief explanation of the apparatus is provided. Needless to say, the unusual musical instrument is almost always in use.
As is seen in the photograph, a person placing their ear near the end of one of the tubes hears a definite pitch. Moving from one tube to the next in succession, the listener hears a musical scale. Some people try to play a simple tune by rapidly jumping from one tube to the next.
To make your own Pipes of Pan, ask your local carpet installer for carpet tubes. The carpet tubes should have a combined length of at least 8 m (roughly 24 ft). This length allows for loss that will occur during cutting. The tubes should be cut to the lengths in the chart below. The chart also shows the corresponding note and resonant frequency for each tube. The tubes may be painted (optional) and attached to a sheet of plywood with small bolts. The tubes may also be simply placed on a tabletop with end stops to prevent rolling.
This Exploratorium-inspired exhibit is visual ambiguity set in motion. As you stare at the shadow of a slowly rotating cube, you notice that it mysteriously appears to reverse its direction of rotation. A quick check of the actual cube reveals that it motion is unchanging. What gives?
Rotational ambiguity arises when the three-dimensional cube is compressed to a two-dimensional projection, removing important visual cues. Finding either direction of rotation equally acceptable, the mind perceives the cube to rotate in one direction, then the other.
As the photo indicates, the exhibit is very simple. A cube fashioned from balsa or soda straws is suspended from a slow turning motor. A slide projector is used to form a shadow of the cube on a translucent screen. Our screen is made of muslin. PVC pipe may be used to form the support for the screen and the motor, but ring stands also work quite well. Two ring stands support the muslin screen while a third ring stand and clamp hold up the motor and cube assembly.
This device may be modified slightly for Halloween. Replacing the cube with a dangling plastic skeleton adds an additional creepy element to an already eerie display.
Interactive Bubble Machine
Who doesn’t like to blow bubbles? With the interactive bubble machine, students can blow bubbles of unimaginable proportions. They can also study the beautiful colors produced by thin film interference as well as standing waves on the surface of the film.
As the figure shows, the device consists of a PVC frame supported by a wooden base. A PVC rod, attached to a rope that passes over a pulley at the top of the frame, is lowered into a tank of bubble solution. When the horizontal rod is retracted from the solution, a sheet of soap film is produced that fills the space between the upright poles of the frame.
The exact dimensions of the frame are not important. The tank, an inexpensive plastic flower box, is filled with a bubble solution that consists of one part Joy or Dawn dishwashing detergent and six parts water (Note: you may wish to experiment with the bubble solution so as to obtain optimal results). Two lengths of fishing line are used to keep the horizontal dipping rod in the plane of the device’s frame. The two lengths of fishing line attach to the top of the frame, an anchor in the tank, and pass through holes drilled at each end of the horizontal rod.
We have used the bubble machine in a variety of venues and found it to be one of those things people can’t keep their hands off of. We have placed the device in the hallway, at the back of the classroom, and, with certain modifications, in a display case. Regardless of the setting, everyone feels challenged to produce the largest bubble. As the figure shows, this can often be achieved with two people blowing on the soap film.
If the bubble machine is placed in the hallway, the floor can become slippery due to spilled bubble solution. To circumvent this problem, we purchased a rubber mat with holes in its surface that allow for drainage.