Hints for Presenting the Pinhole Inquiry:
Prepared for the May '99 PDD workshop

Draft

"starting point" activity with the pinhole boxes (we take about an hour):

tell people at the beginning that the purpose of the starting point activity is to get familiar with the phenomena, the materials, to define a topic for inquiry (pinhole phenomena) and to raise questions --- so try to remember and/or write down questions as they come up for you.

3-4 people per pinhole box.

a different filament in boxes on adjacent tables (or adjacent boxes on the same table).

we start with the following at each table --- a cup with pushpins, masking tape and extra masks, screens

after about 10 minutes, have flashlights/mini-mag lights prepared to hand out if people are trying to peek into the box to see the light bulb (have them turn the light off so they don't blind themselves)

after about 20 minutes, hand out cups with different sized nails in them so people can make larger holes (large holes allow people to see the entire inside of the box instead of just the filament)

if people are trying to make long slits with the pins, give them a mat knife.

if people are looking at the different orientation of the image out of each window, eventually, show them how you can rotate the fixture at the top of the box.

if people have large hole and an image of the inside of the box, an interesting thing to look at is a pen place down through one of the holes in the top of the box. This shows the reversal because a pen placed in the left hole shows an image on the right side.

people often ask if the holes (on top) are crucial for the images. If they are exploring this for a long time and getting stuck, you can tell them they are for ventilation.

images drawn on the paper table cloth inside the box can be seen outside the box if a screen is held above the hole.

encourage people to look at each other's work, especially when one group has a particularly interesting image/discovery.

give people a five minute warning before stopping.

***
eliciting questions and observations:

sometimes people who have just been through the ice balloons activity are very hesitant to ask questions that they don't think are investigable.

Encourage people to put forward both their observations and questions at this time and don't worry about them being perfect. Later on, people can change observations into questions and turn non-investigable questions into investigable ones.

Put forward questions even if you know that your going to work on something else --- someone else may adopt your question.

we start by taking 2-3 examples of observations/questions out loud and model writing it on a sentence strip --- if the question needs to be re-phrased to be comprehensible, this can be modeled out loud, and people can see the size you are writing so the questions can be seen easily from a distance.

Then, tables write and post observations and questions themselves

***
doing the "mini exhibits" starting point extensions:

these raise a greater variety of questions when you collect the next round. They also show more aspects of the phenomena and show more of the tools that people can use in there investigations.

Pinhole viewer: If you have a bright day and can see outdoor objects, great. If not, you can set up a red and blue light next to each other - this really confirms for people that pinholes reverse objects and more questions about reversals seem to come up. Unless people make the viewers themselves (or are shown how they are made to save time), they often get the idea that the image is cast on air, instead of the wax paper.

die cut cards: we set these up with a fluorescent light and a c-shaped bulb. They help people see things about size and shape of pinhole and about multiple overlapping images (on the long slits).

refrigerator box --- if you can do this, great --- people really get insights about how light reflects off objects. it's got to be bright outside.

antipinhole: the easiest way to do this is to have two people to hold fluorescent lights in a cross for you while you show the clay ball on the string to make the cross shaped shadow and the pinhole to make the cross shaped image. To make a simple "antipinhole bulb", have someone put their hand over a part of one of the fluorescent bulbs while looking at the shadow of the clay ball --- a bright spot will appear in the center of the shadow --- "why does it get bright when you take away some light with your hand?". A more sophisticated anti pinhole bulb is a soft-white 75 watt floodlight (with a flat front) and an large arrow drawn on in with black permanent marker --- turn the light on outside for 10 minutes after drawing on it to let the pen vapors burn off). This demo is helpful for groups where there are some people who have had more experience/knowledge (or think they do) with light. It gives them a seemingly more advanced place to start investigating.

***
collecting more observations/questions:

Doing this again after the "exhibits" seem to get a good variety. We ask each person to try to think of at least one.

**
sorting questions/observations:

they usually fall pretty evidently into the groups - reversals, size and shape of pinhole, clarity and brightness of image, image (including reflections/colors - the miscellaneous-bin category for thins people see), geometrical relationships, anti-pinhole, and "beyond the domain of pinholes" (the miscellaneous-bin category for things that are hard to investigate such as relationships to the eye, or are about different topics altogether).

***
Moving from exploration to investigation:

at this point, it has been helpful to set expectations - let people know how long they'll be working and what will come next. Alert people that some will start with a burning focus, and answer their feel done in 20 minutes and not easily get re-started on another question, others will have to explore for awhile longer before they can get focused, others will try a variety of things, and not be able to answer their question or get more confused and feel frustrated. There are many ways to get stuck. One of the biggest insights about the process is that there are many ways to get unstuck, and the biggest breakthroughs are often right at the point where you get "unstuck". Let people know what supports they have - talk to a facilitator, look at what other groups are doing, draw a picture or reflect on a journal to get your thoughts on paper, or take a quick break.

Encourage people to stick with it because at the end, they'll be a chance to share out discoveries, and that each group will have found out one piece of the puzzle which has more of a chance of providing more comprehensive understanding if everyone finds out as much as they can.

Finally, one of the big outcomes of the process is that you usually end up with more questions than you started with - one question usually leads to another (or several more), and one way of noticing this is to keep a journal and quickly record interesting side questions that come up as you are investigating your main question. This way, if you answer your main question, you can look back and pick up some of the others that came along the way. Or if you get stuck on your main question, maybe some of the side questions will be helpful alternate paths to get to your main question.

***
forming groups:

we model having people form groups by interest, so that people's passions fuel their investigations. We also ask that they work in groups of two or three so they have someone to bounce ideas off of and the groups are small enough so everybody participates fully.

our current group-forming method is a "gallery walk" --- where the sentence strips are posted on boards titled with the above categories and distributed around the room. People look at the questions, congregate where they are most interested, and get into sub groups of two or three based on their particular interests. We've found it helpful to ask sub groups to write out what question/observation they want to work on, what materials they want to use, and what they think they'll try first. This help them to pre-think their plan --- and to help the facilitator gather materials for groups quickly.

This isn't the only way. You may have good reasons for forming groups other ways, and often, your teachers are the best source of ideas for forming groups.

***
hints for facilitating investigations:

reversal --- talk to people. Listen closely. This is often the group where people feel least secure, and reassurance really helps. After people have been working for awhile, it can help to ask that people draw or build a model of what they think is going on. That way, the thoughts, ideas and hypotheses are made public and can be looked at. Sometimes it helps to hand a group a red and blue light and a couple of long dowels. This seems to suggest that light travels in straight lines (like the dowels) and help people to begin to construct a model. String also helps with the models.

Often, people ask for mirrors and lenses before they do anything else. This can be ok, but it more often distracts people because the phenomena of lenses and mirrors is different from pinholes. Mirrors only reverse left-right, not up-down, lenses really do bend light, pinholes don't...when people ask for these, try to talk to them about what they really want to find out. Perhaps, another piece of apparatus will be more appropriate.

Often people want to re-reverse the image using mirrors, lenses or the pinhole viewers. Keep the focus on what the pinhole is doing as much as possible. Sometimes, it can be so satisfying to "solve this challenge that people feel good about the inquiry process from this perspective. If they come up with the understanding that pinholes and lenses/mirrors are different that's a step, and hopefully another group will figure out more of the reversal piece and report to the whole group so everybody gets it. For groups trying to re-reverse the image with the pinhole viewers, it's hard but possible, have them draw pictures eventually to check if they are aware that the image on the 1st piece of wax paper becomes the image for the 2nd pinhole to reverse. The light needs to be very bright and very directional (the v-shaped filaments on the candle bulbs work well).

Image: some people work on the "ghost image", the secondary images that are fainter and often reversed from the main filament image. These are reflections of the filament onto the inside of the back of the bulb (like a mirror). After letting people work for awhile (people have come up with ingenious ways to block one of the images but allow the other to stay...) one way to see the reflection image clearly is to give people a dimmer switch, turn it way down, and look at the bare bulb on the table. You can see the fainter reflections of the filament on the back of the bulb. Another tack is if people suspect it's a reflection off the bulb like a mirror, give them a mirror to see if they can replicate the "ghost" with a mirror. Asking people to draw where the light is going can be very helpful for this group.

Some people wonder if the wattage of the bulb affects the image. Having dimmer switches is useful for this question.

some people are excited that large, full color images get through the pinhole. If they are looking for something colorful to put in the box, you can give them colored pens and they can tape things they've drawn into the box to see if the image can project out. Larger holes make the object more visible but less focused - people who notice this can talk to the group doing size and shape of pinhole. This group is also dealing with reflection issues - light needs to reflect off objects for them to be seen. You might ask, why don't you see the image outside the box when the light isn't on?, or, where is the light coming from?, or encourage people to compare the brightness of objects of different colors (white is clearer because it reflects more light than darker colors).

Size and shape of pinhole/brightness and clarity of image:
these two are essentially about the same things - the bigger the pinhole, the more multiple, overlapping images come through, the images add there brightness together so the combined image is brighter but the individual images don't fall in exactly the same place so the combined image is fuzzier.

The die-cut cards can help here, as well as giving people mat-knives and nails to make big and small holes.

What is particularly helpful is referring to the clap-light demo - that without the pinhole, the screen is full of images, and the pinhole allows only one (or a few).

geometrical relationship: if you give people rulers/yardsticks for measuring, the most difficult thing is what to measure. If people are trying to measure from inside the bulb, from inside the box, to see how big the image gets, it can get too messy. It helps to pull the bulb onto the table, or even, to use a fluorescent bulb so that they don't have to guess about how far the filament is from the outside of the glass. Also, you can use two mini-mag lights with their tops removed. These provide point sources of light and you can get very accurate measurements of how far apart the light images are holding the screen at different distances from the pinhole.

For people interested in the significance of the orientation between the bulb, the pinhole and the image, the best way at this is to get each of these out of the box and onto the table.

anti pinhole: several ways at this are to after listening to how people make sense of the crossed shape shadow, to:
If people are struggling with the smaller bulbs with the black arrow in them, give people a large fluorescent bulb and tape a piece of black paper in the middle. It's not only easier to see because it's so big, it also seems easier for people to think of this as two separate light sources that cast two separate shadows of a clay ball (with no shadow in between), than one light with a black shape in the center that casts one shadow with a bright spot in the center.

Or use 3-5 mini-mag lights with their tops removed and cast 3-5 shadows of a ball on a screen. As the ball is moved closer to the screen, where the shadows overlap makes a darker shadow until when the ball is against the screen, there is only one dark shadow of the ball. It's easy to see that the right hand ball casts the left hand shadow. It also seems reasonable for people to see what happens when you turn off the center light (the dark overlapping place where that light cast that shadow gets less dark - and so looks brighter by comparison - but the whole screen is also comparatively less lit up because there is one less light shining onto it). Multiple light strips, or vanity lights, can be helpful here too.

It's very helpful to keep referring people back to the clamplight demo here - if the wall is full of overlapping images of the lightbulb, then a shadow is a missing image (and so it's negative). One way to show this is to have a peg board so there are many images of the bulb with the arrow on the wall. Hold a clay ball on a string right against one hole so it blocks the image completely. Now, take the pegboard away while leaving the ball there - the image from the ball fills the image from the pinhole like a puzzle piece.

The smaller the clay ball, the clearer the image. Some people found that a poppyseed taped to a piece of overhead acetate gives a great antipinhole image.

***
Mid way through the investigation: if you can stop people and briefly share out here people are in their process, people will notice that some started out hot and got cold, some started out cold and got hot, and others have fluctuated. It's the getting unstuck part that's most difficult and most important and people realize they aren't the only ones getting stuck. . This discussion also allow the facilitators to get a handle on where particular groups are, who should talk to whom, and who may need extra attention.

***
towards the 2nd half of the investigation: as you see groups make discoveries, encourage them that what they just found is an important piece of the whole picture of pinholes, and to consider how they might best share this information with the rest of the group in 2-3 minutes - whether describing what they found in words, through showing what found with a picture, or through demonstrating what they found with their apparatus.

Look especially for people who have found ways of convincing themselves that light travels in straight lines, elegant ways of convincing themselves why pinholes reverse images, ways of showing why big pinholes make bright but fuzzy images, ways of showing that there are relationships between where an object, a pinhole, and a screen are, and what the size of the image is, and anyone who has elegant ways of explaining the anti pinhole.

***
sharing out:
This is a critical step in making sense of people's experiences. It is a way of distributing the expertise in the room so everyone builds a more comprehensive understanding than they were able in there own investigation. This makes the point, like no other, that having groups investigate many different things and put them together is actually an efficient way to find out about a complex topic, instead of seeing the investigation as spending a very long time to do only your own isolated investigation.

We structure this fairly informally - people can present in 2-3 minutes, but only if they want to. If enough people have been tapped and encouraged that they have something very much worth sharing, others usually feel less threatened. We've tapped someone on the shoulder ahead of time to go first, from the group that did reversal and got excited about some discovery they made. As an introduction we ask that groups working on reversal share at the beginning, groups that did antipinhole share and the end, and others go in-between.

Keep track during the presentations of who discovered what so you can reference this when you do a synthesis

***
synthesis:
at the end of the sharing, it's helpful to spend a few minutes synthesizing people's presentations. Preface this by saying that you are basically repeating and reconfirming what the group found out, not lecturing and giving the answers. By taking peoples presentations and putting them into the context of the big ideas underlying pinhole phenomena, you confirm what important things can be found out, and validate the group because many or all of these things were found out.

big ideas:

1. light travels in straight lines
2. light travels in all directions at once from a light source
3. light reflects off objects
4. your eye is a light detector

Usually, some group(s) find an elegant way to confirm 1. If you haven't seen any group confirm 2, the clamplight demo does that (all those images are coming from one place, so they must be going in al directions at once).

By taking 1 and 2 together, the implications explain several things.

Groups that figured out reversals drew on these ideas. They usually use straight lines (sticks or string) to demonstrate the reversal, and light could go any direction, it's just that the only direction it can go to get to the screen is through the pinhole - so pinholes are selectors of light, not reflectors, focussers or benders of light.

Groups that figured out about size an shape of pinhole effecting the brightness and clarity of the image drew on these ideas. A tiny pinhole has effectively one path for the light to take to get through it so it lands on the screen in one place. A big pinhole has several paths for the light to take through it (center, left side, right side, upper side, etc.) and so, while more light gets through (so the image is brighter), the lights ends up in slightly different spots on the screen so the image is fuzzy (the images overlap instead of layer perfectly on top of each other).

Groups that worked on geometrical proportions drew primarily on 1 and their knowledge that pinholes reverse images. As long as light travels in straight lines and reverses through a pinhole (the standard diagram with crossed lines that meet at the pinhole), this means you have similar triangles between the image, the object and the pinhole - and similar triangles have proportionate sizes between the height of the object and its distance to the pinhole and the height of the image and its distance to the pinhole. This allows you to predict the size of an object from measuring the size of it's image and the distance to the pinhole for both the image and the object.

groups that figured out about the "ghosts" or about how whole images got through the pinhole were drawing on and confirming the idea that light reflects off objects (idea 3.). The "ghosts" were a mirror type reflection.

The way whole objects get through pinholes is that they have to reflect light from some light source. Our eye is a light detector (idea 4.) - if we can see something, there must be light reflecting off of it. And the light that reflects off objects acts just like light sources (goes in straight lines, goes in at directions at once), only dimmer. Groups have probably seen objects upside down like trees through the pinhole viewer or letters through the light boxes.

***
final comments:
you may want to give over a few minutes to the group for comments. You may get a mix of comments, some from people who are still uncomfortable with the process, and some testimonies from people who feel like they have learned something for the first time, even though they had been told it for years.

***
discussion and debrief:
at this point, it is critical for people to have a chance to think and talk and begin to make sense of the process and structure of the inquiry experience, so they can think about how this could apply to topics in addition to pinholes.

We do this in small groups (less than 12) so everyone can talk, and start with a prompt like "how did it feel doing the investigation". This lets people return to the experience and get whatever they need to say about it said so that they can start to consider the structure objectively. After people have talked awhile, another prompt is, what structures were present that helped this to work (in as much as it did). This discussion helps people to confront the common myth that inquiry is unstructured. Part way through this discussion, we pass out the sheet called: structure of the inquiry experience (starting points, materials, facilitation, sense making), so that people can use this as a jumping off point, and as a way to remember what they went through.

Add any prompts that will encourage the kind of discussion you want your particular group to have.