1. A plastic or glass transparent blank is required. 10cm X 3 cm. I cut it out of the sub-disc with a heated nail file.
2. A metal rectangular blank is made. 9cm X 1 cm.
3. bends
4. Using a drill 1 mm - 3 mm, a circle is made. The smaller the diameter of the circle, the better.
5. Now drop glycerin or water onto the circle, look very closely at the circle, pressing the middle of the piece of iron to approach the object of study.