Different Seasons
We divide the year into seasons by weather patterns. Most of the United States has four se...
Pinhole cameras are so simple that people sometimes don't believe they will work. But physically they are almost identical to the human eye. The eye is a ball-shaped chamber. Light enters through the hole of the pupil and shines on the retina on the back of the eyeball. Likewise, the pinhole camera is just a box with a tiny hole in the middle of one of its faces. When you secure a piece of photographic paper inside the box on the side opposite the hole, the camera is ready. Because the box must not let any light in, it is usually taped closed with black electrician's tape. When you open the pinhole light enters the box and projects onto the light-sensitive paper. You have taken a picture. Later, you develop the paper in a darkroom with special chemicals. A negative image appears on the paper which means that dark things look light and light things look dark.
We divide the year into seasons by weather patterns. Most of the United States has four se...
Every fall, the leaves on some trees turn different colors. Leaves are green in the spring...
Ecosystems are communities of living things that are made up of different shapes and sizes...