Science Buddies: "Ask an Expert"

Through this forum i have an unsolved problem: When we conducted an experiment to observe the image properties that resulting by reflection or refraction of light by using a concave mirror or convex lens, such as an object is a candle or lamp bulb, when we place a lighted candle or lamp bulb at a certain distance in front of the mirror or lens, why when formed real image captured by the screen only shape of fire on a candle or light on a lamp bulb? While rod of the candle or lamp bulb not appear on the screen.

Any light produced by the candle will travel through the lens and appear in the image. You see the flame because it's a light source. The candle itself won't directly appear because it's not a light source. If you shine a bright light at the candle and let the light reflect off of the candle and through the lens, you will see that image as well. The setup you're describing with the convex lens is also known as a 'camera obscura'. You can find all sorts of information about them on the web.

http://ndrdmath.weebly.com/camera-obscura.html

I generally agree with HowardE. However if you are not making a camera obscura I would wonder about the size of the lens or mirrors. If they are too small you will get the same effect you described.