Topic: Convex lens.
Can a magnifying glass burn paper?
I think you have gone nuts.
No.
It is possible.
What?
But how?
It is because a magnifying glass is actually a convex lens.
A convex lens is thicker in the middle and thinner at the edges.
Like a fish?
Absolutely.
This shape of the convex lens makes the parallel rays of sunlight to refract.
Such that they converge or come together at a point.
So, when they come together, do they have a party?
Please listen.
As the rays converge, the concentration of sunlight at that point increases, thus producing heat.
This heat starts a fire which eventually causes the paper to burn.