Is it Real or Virtual?


  • Concave lens (lens that caves in on both sides)
  • Convex lens (lens that bulges out on both sides)
  • Any object
  • Sketch pad


  1. Look at an object with your concave lens.
  2. Draw the image you see
  3. Look at an object with your convex lens.
  4. Again, draw what you see. How is the image different?


When looking through a lens, there are two types of images that you could see. The concave lens should have given you an upside down image, also known as a real image. As light goes through a concave lens, it refracts and converges after exiting. However, it converges underneath the principle axis and looks upside down.

The image you saw through the convex lens is called a virtual image. A virtual image occurs when rays of light enter a lens and diverge after exiting. As a result, it looks like the light is converging at a point where it really isn’t, hence the name virtual image. You can identify a virtual image because it will be upright, look smaller than it is, and look closer to the lens.