How do you make a Fresnel lens?

Take the lens into a place where the sun is shining. Hold the lens between the sunlight and the object you wish to burn. Move the lens nearer or further away until the lens throws a small usually...

Water and salt.. Im not sure on the measurements though, sorry.

A4 plastic sheet magnifiers are a good version of fresnel lens.

The lens is connected to the inside of the front part of the eye by muscle fibres which form a radiating ring around it. When we wish to focus on close objects, these fibres relax, and the lens...