I made myself a pinhole projector to see the solar eclipse on a piece of paper. Making the projector was super simple: I took a bit of cardstock from a soda box and poked a hole in its center with a pin. Then I held it between the sun and a piece of paper, so the shadow of the projector fell on the paper, and there, in the pinhole, was the image of the eclipse.
The way it works is presumably simple as well, but I don't fully understand it. The sun shines on a piece of paper. If something gets in between the sun and the paper, there's a shadow. Well, during a partial eclipse, the moon gets between the sun and the whole earth, but there's enough ambient light that the paper is still fully lit. But if you put the pinhole projector between the sun and the paper, the shadow of the projector falls on the paper, and the light of the sun only goes through the pinhole, making a bright pinhole spot on the paper. When the sun goes through the pinhole, it shows its obscured-by-the-moon self to the paper because there isn't room for the light to disperse. Why it shows up upside-down and backward, I don't understand at all...! According to Hartebeesthoek Radio Astronomy Observatory (HartRAO), it's because light has to travel in straight lines. But I don't see how light traveling in straight lines through a little hole makes an image flip.
What I wasn't expecting was that this pinhole projection effect is found in the shadows of trees, as well! (HartRAO explains that, as well, but I didn't know it before the eclipse.) It was really cool to see the shadows on the sidewalk near me, and to see how they corresponded with the image on my paper. Here are two sets of images: the sun before 99.2% obscuration, and the sun afterward:
All around me, people stared upward with their solar glasses, but I liked to see the world around me, instead. As the moon covered nearly all the sun, several things happened at once: the daylight dimmed to a strange gloaming or twilight; the air got colder and I got goosebumps; strange fluttery waves of light and shadow, very subtle, danced on the sidewalk; and people and animals alike grew silent.
As the sun began to show itself again, the air warmed up, and people started to disperse. Most talked happily about how cool it was, except for a few who were determined to be unimpressed. One weird aftereffect was that several people mentioned feeling a little lightheaded and weird. I felt the same... like I was a little off-balance. I wasn't sure whether it was because of the eclipse or the fact that I was up late last night and early this morning, but several others couldn't all have that excuse. It didn't last long, at any rate.
Overall, a very fascinating experience!
Blogs I Read