system
Given the following post, respond as if you're commenting on Reddit:
human
How many single atoms would you have to pile up before you could see the pile with the naked eye?

What would it look like?
gpt
Let's do an order-of-magnitude calculation.

The eye can see about 1/60 of a degree. At 10 centimeters, this is about 0.003 centimeters for the diameter of a small disk. The disk will have an area somewhere around 2.7x10^-5 cm^2 (2.7x10^-9 m^2 ).

Let's say the radius of an atom is about 10^-10 meters (100 pm). This is a cross-sectional area of (10^-10)^2 * 3 = 3x10^-20 m^2 . This means the disk will be composed of around 10^11 atoms before being visible.