Have you ever taken a picture with a camera and then wanted to make a copy of it? A slide copier is like a special camera that helps you do that!
You know how when you want to draw a copy of something, you put paper on top of it and trace over it? A slide copier is kind of like that! Instead of paper and a pencil, you have a camera that you can attach a special lens to.
You take a small picture called a slide and put it into a part of the copier called the holder. Then you turn on the camera and when you look through the lens, you see the picture on the slide!
But instead of drawing it, the copier takes a picture of it. The camera takes a picture of the slide, and then you can see it on your computer or print it out to make a copy of the picture!
So when you want to copy a picture, you can use a special camera called a slide copier to make an exact duplicate. Isn't that cool?