Frank Oppenheimer

Day 1: Exhibit Explorations

with Paul Doherty

Science begins with observation, and yet, students in science classes seldom get to study perception formally during class. Informal science explorations at science centers can fill this need. Science exhibits allow people to explore how two different observers can look at the same phenomena and yet have two different perceptions. Every person sees something different and yet all are correct.

To understand what is, we must first learn how it appears.

What do you see? Try this!

As a guide at the exhibits I am there to facilitate exploration by teachers, students and museum visitors. With teachers or students at exhibits I start off with the question, "What do you see?" I like the question since it is hard to give an incorrect answer. On the other hand, with museum visitors I start off by saying, "try this!"

Let's go to some real exhibits and see how they can be used for exploration.

Here are the exhibits we will explore:

Comparing Yellows, Did you ever wonder whether everyone sees the same colors that you do? Here's an exhibit that let's you explore this question.

Laser Speckle, Scientists must be honest reporters of their observations, even if it means not going along with the crowd.

Find the Highest Note, A fine acoustical illusion, the pitch you hear is not necessarily the pitch that other people hear.

People's perceptions of the same phenomena may be different. To study a natural phenomena, scientists must perform experiments which get around these human perceptual differences. Thus, scientists must take into account the human perceptual system when they evaluate "eyewitness testimony" to natural events.

Points for Discussion

As we study science in this course the answer to many questions will involve differences in perception. I'll point out these perceptions as they occur. Also keep your eyes open for reports in the newspapers of UFO sightings. Very often these sightings are natural events. Observers truthfully report what they perceive. To understand the natural event you must understand how the human perceptual system works.

Honesty is very important in science. As we go from exhibit to exhibit I'll ask "What do you see?" I need an honest answer from each class member. Even if your answer is different from everyone else's answer, even if the answer you give does not seem like the one that I, the teacher, want. This is a science class and honesty is most important. Through your different perception we might all learn something new.

Etc.

My Explorations can be summarized in the simple phrase "Everyone sees something different yet is right."

Linda Shore's explorations can be summarized with the phrase, "Everyone sees the same thing yet is wrong."

Lao Tsu said "The world is not as it seems, nor is it different."

This day we are going to do classroom explorations based on exhibits.
These explorations use simple, inexpensive, materials.

By choosing the materials which I provide the class I provide subtle guidance as to what explorations are possible.

I begin by distributing minimaglites which provide bright points of light. I dim the lights in the room and once more ask teachers "What do you see?" Someone will see and report bright lines radiating from the lightbulb. I then give the class a challenge. Do experiments to show where the rays are located in space.

After some exploration time to allow experiments with simple materials I ask small groups of teachers to report their observations, experiments, and hypotheses. A second round of observations may follow the first and a second round of discussion.

If there is time a second exploration is possible by observing the afterimage of a moving minimaglite.

Locating Rays.
Look at the bright bare bulb of a minimag light, "What do you see?" You will probably see rays of light spreading out from the bulb. Here is an exploration in which you search for the location of those rays in space.

Afterimage
Move the minimag flashlight bulb around in 3-D in front of your face. Notice the colored afterimage of its trail.

Diffraction
You can see diffraction of light as it passes through a narrow slit held near your eye, or around a narrow object such as a hair.

This page is available on my website http://www.exo.net/~pauld

Many similar explorations are also available at http://www.exo.net/~pauld/site_map.html

Scientific Explorations with Paul Doherty

© 2003

14 October 2003