Extending Observations of the Pinhole Phenomena

First, Emily reviewed the powerful ideas about light, shadows, and the pinhole phenomena:

• Light travels outward in all directions from a light source (evidence: light dispersed on a screen from clear light bulb with vertical filament)
  
• Light travels in straight lines (evidence: shadow formed by obstacle in front of a light source)
  
• Light travels outward in all directions from an object one can see (evidence: an image of a light bulb can be seen shining through wax paper of a pinhole camera, Emily's nose can be seen by everyone in the classroom, regardless of which table they are sitting at)
  
• To see an object, light has to travel from the object to your eye
  

We hoped for sunny weather but unfortunately, by the time the class had made it outside, clouds covered the sun. Instead, we continued our exploration of pinhole cameras inside. The students used a light bulb, aluminum foil with a pinhole in the middle, a wax paper screen, and a meter stick to work on a new type of pinhole experiment. We asked them to use the materials to build a pinhole camera similar to the one they built last week. Emily, Kortney, and I walked them through setting up the following proportion:

Height of Object (actual light bulb) / Distance of Light Bulb from Pinhole
=
Height of Image (image of light bulb on screen) / Distance of Image from Pinhole

OR:

h/d = H/D


Students working on finding measurements


Image of light bulb on wax paper screen








This particular group decided to focus on the way that the height of the image changed in relation to the distance of the pinhole and screen to the object. They realized that the further away they moved the screen from the object, the larger the image would appear.