OVERVIEW AND PURPOSE

From the moment we wake up to the moment we go to bed again at night, we use our eyes to take in information about the world around us. Indeed, 70% of the receptors in our body are in the eye. Looking and seeing is something we do so often, we don't even think about it. This presentation has the goal of probing students to start asking questions about the everyday phenomenon of light and sight.

What if we could shrink students and bring them on a field trip inside an eye? While unfortunately I cannot actually do this, the next best thing is transforming your classroom into a camera obscura. This is latin for 'dark chamber' which is, at its very basic, what the eye is. So come, let us explore the marvel of sight together!

Lets be fools for a moment, let our jaws drop at the mundane beauty of light. Let it disturb us that we can see, and let us then ask how it can all be

Eloise Faehndrich UBC 2021

DESIGN

Step 1: Make room dark

Cover all windows, and cracks in the door using black paper/garbage bags. Use black tape to get all the small openings.

Step 2: Make sure the wall that the image will be projected on is as clear as possible

If needed use a white sheet so that the image is as easy as possible to see

Step 3: Make a hole in the black paper

The hole should be as circular and clear cut as possible so that the image is as clear as possible

Step 4: Have fun!

Try playing around with moving a paper closer and further apart, using a lens to focus the image, increasing and decreasing the pinhole size. If you use wax paper, you can see the image from 'behind the screen', which sometimes makes it easier to see.

Other idea: Refrigerator

Another fun idea is to do the same thing inside a refrigerator box so that you can transport it to different places and get different images on the back that you can try to trace out if you are so inclined.

Step 1: Make a pinhole

Using a small nail or pin, make a small hole in a piece of aluminum or metal sheet. If you want to be really specific, the pinhole should be related to the focal length of your chosen camera using the relation: 𝒅=𝟏.𝟗√(𝒇×𝝀), where d is the diameter of the pinhole, f is the focal length, and 𝝀 is the wavelength of light coming in (sunlight has the majority of light at a wavelength of 502 nm)

Step 2: Choose a container and attach the pinhole to it

Use black tape to not allow any light to come in the sides. Also create a flap out of black tape that can act as a shutter to only allow the desired amount of light in.

Step 3: Put the instax mini instant film paper inside camera

This is a crucial step and needs to be done in complete darkness. First you need to take the film paper out of the black cartridges they come in, then transfer one sheet into the camera (when using instax make sure the backside is facing the light) while putting the others in a light proof container to use later. Finally you need to close it all up, again using black tape to cover up all edges.

Step 4: Take a picture!

You need to know how long the shutter should be open for, which depends on the lighting conditions as well as the size of your pinhole. Here is a table I started out as a baseline and then twiddled with to figure out what works best (taken from here)

Step 5: Develop Image

Each instax film sheet has pods of that hold the chemicals that stop the light sensitive paper from reacting with the light. Once you have taken your photo, go back to the dark room and squish the pods located at the bottom of the paper, and use your fingers to spread the chemical over the whole image. Let it sit for roughly an hour. Don't worry if you mess up the first few ones, it takes a couple to get used to what it feels like!

PRESENTATION

Here are the slides I used for my presentation, as well as the worksheet.

Some tips I was a one time presenter in the class (as in the students did not know me ahead of time), and so I included a slide about me, which I felt would make the students feel more connected to me, if you are doing this presentation for your own class, obviously you don't need to include such a slide. I was also presenting remotely (in the covid era), while the students were in person in the classroom, and so I had to get creative about how to engage the class. I used pollev.com, an online polling site that allows you to create polls, and got the teacher to get the students to bring their phones/tablets/laptops to class to participate. If your class is all on zoom, there is a polling feature on zoom that you can use, as well as get students to annotate your slides at the appropriate moments. If it is in person, obviously you can just talk to the students and have a discussion in person [seems like a luxury now from a bygone era :) ].

Finally, encourage questions! Throughout my presentation I sought to show students how asking questions can lead to figuring out a whole lot more about how stuff works, and how exciting that can be!