What Does It Mean to Do Science?
Two inquiry lessons for teachers/students/whoever needs to learn.

Introduction
As a colleague of mine told me, science is about first describing what you see and secondly, trying to come up with an explanation in terms of what you already know. In working with teachers and students in many workshops I have tried to use exercises that emphasize this fundamental view. Below are two exercises that model good teaching practice and have had strong positive response from teachers in a variety of programs. The exercises are active, interactive, and thought provoking. Neither activity is really "new." I have heard that the box activity goes back to the 1950’s but I have not found a reference. The disappearing test tube is an old physics demonstration, recast as a question and answer.

Each activity involves a guided dialog with the group, and, in the second case, the students working in pairs to conduct an investigation. There is no prerequisite science content, and in fact, either activity could be used to show parents how inquiry helps their children learn.

• Disappearing Test Tube
• What is it? (a.k.a. White Box Activity)

The Disappearing Test Tube

Materials

• A beaker of about 400 ml capacity
• A pyrex test tube
• A vegetable oil. Wesson Oil seems to work best with a pyrex tube. The oil must be matched to the optical index of refraction of the pyrex.

The Activity

This is an interactive demonstration about how we see things. The students are gathered around so that they can see a beaker and a test tube that I have placed on a table so they can be seen at eye level. Then we begin a discussion.

What do you see there?

(the students describe what they see — beaker, test tube, table)

How is it that you are able to see the test tube and the beaker. Aren't they both transparent? Aren't they both colorless?

(the students will provide many answers. Hopefully some point out that they see light reflecting from the beaker and tube. Also when they look through the beaker and tube they see the objects beyond are distorted).

I have a bottle of high tech liquid in my hand. The label says "Wesson Oil." I will pour this liquid into the beaker but not into the test tube. (Fill the beaker with Wesson Oil.) What do you see now? Can you still see the test tube inside the beaker? Do the reflections that you saw earlier look the same? Does the test tube look the same? Do the distortions that you saw earlier look the same?

(Listen to student responses. Discuss what they say.)

Now I will pour this oil slowly into the test tube. (Fill the test tube half full with Wesson Oil.) What do you see now? Can you still see the test tube inside the beaker? Do the reflections that you saw earlier look the same? Does the test tube look the same? Do the distortions that you saw earlier look the same?

(Listen to student responses. Discuss what they say.)

We have done a good job of describing very carefully what we have seen. Now let's think about the second part of the scientific process. Think about how you were able to see the test tube before, that is, because of the reflections and distortions. Are they still there? From what you know about reflection and refraction, how would you explain what you have seen?

The discussion may lead to the fact that the test tube disappeared because the reflections and distortions that made it visible in the first place have been removed.

The scientific explanation for this demonstration is that the index of refraction of the oil is almost the same as the index of refraction of the pyrex test tube. The matching of indexes removes reflections and refraction of light at the surfaces where the oil and test tube meet. The index of refraction of the beaker does not matter. "Index matching" is commonly used on camera lenses to reduce reflections from the glass lenses.

The scientific explanation is not important for this demonstration. The observation and discussing what you observe is important.

What Is It?
(a.k.a. White Box Activity)

This second exercise also starts off with a short discussion of how doing science involves first, description and second, developing an explanation that fits the description.

Materials

• Small 3" x 4" white cardboard boxes that can be taped closed. I buy small gift boxes at a party or paper store. Either one per student or one per pair of students.
• Each box should have one or more small objects in it. For instance: nails, rubber erasers, small magnets, small balls, clothes pins, ping pong balls, blob of modelling clay, etc. Put only one type of object in each box.
• Tape the boxes shut with clear tape. Put a number on the outside of each so that students can identify their own boxes. It is good to put identical objects in some of the boxes so that there will be "twins." (See below)

The Activity

I hand each student or pair of students one box and ask them to take out a sheet of note paper. I am a nuclear physicist so I tell my own story, which you can adopt as you need be. Do not be afraid to try out the nuclear physicist persona.

In my research life I study the nucleus of the atom by throwing neutrons at nuclei and measuring how the neutrons bounce away. The nucleus is so small I can never see what is inside, but through my neutron bouncing experiments I can describe a lot about the contents of the nucleus. I have an activity that is similar to studying the nucleus. We are going to do careful measurements and descriptions. Then we will try to hypothesize a description that explains our observations.

I have given each of you a sealed box with a number on it. You have already shaken the box and realize that it contains something. We are going to investigate the object in the box - without opening the box. This exercise is sort of like what your students do each Christmas season with the boxes under the tree, but we are going to do this as a scientist would. I have done research in nuclear physics and measured many properties of the core parts of the atom. Even though I have learned much about the nucleus I have never seen a single nucleus alone. I never get to open the box and see directly what is inside.

So let's begin our scientific investigation. You can shake, hold, smell, listen, or whatever, to your box, but you cannot peek inside. You and your partner should write down the number on your box and five words to describe what you sense about the object or objects in the box.

(Give the students a few minutes to do this.)

Now sometimes when I am doing an experimental study I walk down the hall to talk to some of the other scientists about their work. This sometimes helps me look at my experiments in a new light, even though they are doing something very different. So now, would you please swap your box with the group sitting next to you and investigate their box.

(Give the students a few minutes to do this.)

Now get your original box back from your neighbors. Handling the other box may have made you aware of some new things about your own box. You can write those down now.

Sometimes when I am at a loss for an understanding of some data I call, write, or email some colleagues and ask "Have you ever measured anything like..." Sometimes I get lucky and get a reply like "Oh, I measured exactly that same thing ten years ago and....." Well, it so happens that each box in this room has a twin that contains exactly the same objects. Now I would like for you to go find the group that has the twin to your box. Talk with them about what they have observed and write down their observations.

(This leads to several minutes of classroom chaos in which everyone goes around the room shaking boxes, talking, exchanging information, meeting new people, and writing notes. The instructor should listen to what the teachers are saying to each other.)

Everyone go back to your seats. I hope you were able to locate a twin to your box and gain some insight about descriptions for the objects in your box. Notice that I have not yet asked you to guess at what the object or objects are.

At this point in an investigation, if not before, a good scientist goes to the library, or the internet, to see if there is anything mentioned about the phenomenon in "the literature." Since we have only a short time I did the literature search for you. I found in our library the four inch thick "Encyclopedia of Little Red Cubic Boxes," which has an enormous amount of information about these items and what is found in them. I understand that we have white boxes, not red boxes, but maybe there are some similarities. In the ELRCB I found that these types of boxes contain only eight kinds of objects. (I write on the blackboard) Nails, ping pong balls, pennies, dice, ....... Each box contains only one kind of object, but can contain one or several of that kind of object. For instance, a box could contain five nails, but it cannot contain nails and ping pong balls.

Now I ask you to look at what you have written and at this literature research and write down on your sheet of paper the type and number of objects in your box. This is your scientific explanation based on the investigation that you have been doing. Show your written answer to your neighbors.

If this were a "real" scientific investigation we would not get to look inside the box and I would take up the boxes now. That would be cruel to do to you. Open your box and look inside? Was your explanation correct? Did the descriptive words you wrote fit the object that you have found? What about the group that had the twin to your box? Did they have the same description and was their box really your twin?

Now close your box back up and return it to me so that I can use it again.

IV. Summary

Both of these exercises have been tested with many groups of middle and high school science and mathematics teachers, and even with adults in a non-school situation. The model of description and explanation models the type of inquiry that is done in physics research laboratories; the process of inquiry is fundamental to producing valid experimental results. The scripts should give you and your students the chance to observe and to talk about your observations. Both of these are basic science learning skills.

Acknowledgement

These activities were honed and used many times in The Science House Student Science Colloquies Program funded by a grant from the Burroughs Wellcome Fund.

David G. Haase and Elizabeth R. Snoke
The Science House
North Carolina State University
Raleigh, NC 27695-8211
Phone (919) 515-6118
FAX (919) 515-7545
Email david_haase@ncsu.edu