Objectives:
Our main objective was to teach kids about the principals employed in still cameras. Despite its antiquity and apparent simplicity, the pinhole camera offers several advantages over lens optics, particularly when resolution is not especially important. These include:
· role of light (pinhole,
distance, sun, etc.)
· how a camera works in
general
· what causes paper to display
an image
· brief introduction to
the role of a dark room
scientific concepts:
* complete freedom from linear distortion
* depth of field a few centimeters
to infinity
* wide angular field
The imaging device of the pinhole camera is a hole punched through an opaque material. The image of a distant point is simply the shadow of the hole - or rather the shadow of the material around the hole. That is, the image is a bright spot on a dark background. When the hole is large, the image of the distant point is large and displays a diameter equal to that of the pinhole.
An extended object is a collection of points; its image is therefore a collection of spots. The smaller the spots, the finer the detail that can be discerned in the object. Therefore, in many ways, the best pinhole is the one that produces the smallest image of a point.
If we make the pinhole very small
in an effort to improve resolution, we will arrive at the situation depicted
in Fig. l(b). Here, the hole is so small that the pattern of light in the
film plane is an Airy disk: the Fraunhofer, or farfield, diffraction pattern
of the pinhole. 8 In this region, the smaller the hole, the larger the
spot. Evidently, the pinhole that gives the smallest spot lies in the region
between the geometrical optics region depicted in Fig. l(a) and the region
of farfield diffraction depicted in Fig. l(b).
We will certiainly not teach kids
all of this, but we will focus on the main light aspects. We must personally
overcome a number of obstacles such as keeping everything light tight,
making the correct hole size, and actually getting kids to learn in a somewhat
complex experiment. This will be hard with a high volume of kids.
Project Description:
We will be teaching the principles employed in still cameras.
The classroom activity will be the making and use of a pin-hole camera. The take-home activity will be the exposing of photo sensitive paper in sun light.
The age group is third to sixth graders.
The children will learn how a basic 35mm camera works, the process of exposure and developing.
This activity meets requirements
because it is a hands on activity aa that teaches children the scientific
principles behind still cameras. It is with in the age group. It has a
in-class and take-home activity. And it will employ a component of manufacturing
using rapid prototyping methods.
Process:
The children were told to
-make a pinhole camera with set materials and explicit verbal instructions
-load the photo paper into the pinhole camera
-cover the hole with their fingers
-take the camera outside and rest it on a solid surface
-take finger off the hole and expose the photopaper for about two minutes
-cover the hole back up
-bring it back inside and let us develope their film paper for them
These are some pictures of us with
the camera materials and the children using them to make their cameras:
This is a picture of the developing stage, viewed outside
the darkroom (very different from the inside):
Success!! :
Results and Observations:
The results from the project were actually a bit surprising to me. The children loved making the cameras and thought that it was so neat that they could make a "real" camera out of just cardboard. They were astounded that some of the pictures came out, and to tell the truth, so were we. I guess we all really learned quite a bit about photography from this project.
The most important thing we were stressing for the children to learn was the dynamics of the pinhole photography. This means the way that the light enters through the hole and projects an image onto the photo paper on the other side of the camera. Unfortunately we tried to explain all this to them while they were building the cameras and not too much of it sunk in. Now that we know better, I think next time it would be better planned to explain to them the science of it before giving them any building materials so that their attention can be completely focused on this instead of the activity. Also, in the beginning, their attention span will be much greater and they will be more open to learning.
It would also be nice if they could grasp some understanding of the developing. As of now, the design only allows for the developer to see what's going on in the booth, but in the future, it would be better to somehow make it bigger or divided with plexiglass so that the children can climb in on the other side and see how the chemicals are working to develope their film.
As far as the results of the photo-taking go, not many pictures turned out, but the kids who followed our instructions properly got some pretty cool stuff!
We learned a lot from this project ourselves. Most importantly, and related to the most challenging part of the project (entertaining kids), we learned that as long as you can show children by example it's much more interesting to them than a set of instructions and they are much more excited about it. Also, there can't be much room for stalling. For example, we unfortunately could only develop one picture at a time. Fortunately, the kids were patient, but that won't happen every time. Attention span and learning by example are the key points in teaching children.