Research & InnovationScience Insider
Have you used a magnifying glass to concentrate sunlight in to paper?
Vidunenahawula Website (National Institute of Fundamental Studies)
In your childhood you may have used a magnifying glass to concentrate sunlight onto a paper. You would see a small patch of light shined on the paper. After some time the paper would start to burn. What could be the reason for the paper to burn? When we see the sunlight we see the light rays of the sun, but we do feel the heat of the sunlight. So, from the sun we get both the light and heat energy. When you use a magnifying glass the heat rays that travel through the magnifying glass gets concentrated at the focal point of magnifying glass. When the paper is kept in this focal point the heat gets concentrated in that area and when it reaches the ignition temperature the paper burns.
