Balloons, Full of Holes!

Write Letters with Atoms

HOP2
Water vapor
which goes through
Cloth

STEP1
Why did the helium
pass through
the balloons?

letters written by atoms

Photograph: Hitachi Seisakujo co. Central Research Laboratory

Now, based on the experiments, you know that there are tiny things called atoms and molecules through the experiments. Here, you can see them.
The letters above were all written by atoms! Pay attention to the yellow grains. As you can see, there are spaces without atoms. The atoms were in their place, but somebody stripped them out with leading edge technology. The places without atoms look like letters, don't they? You can find the letters "PEACE '91 HCRL" in the picture. The scale is below the picture. The size of the atoms in this picture is about 0.2 or 0.3 nm (1 nanometer = 1 millionth of a millimeter).
Atoms are extremely small, so you can not see them with normal microscopes. The pictures were taken with a special microscope.
Let's see another picture, taken by a special microscope.

Note
This picture shows a letter written by removing sulfur atoms from molybdenum disulfide. The technology of Scanning Tunnel Microscope (STM) is applied to write atomic letters. STM is a microscope which can get 2D images of atoms by moving a metal needle towards the object surface until about a few atoms close, and then scaning the surface with keeping that distance. HCRL stands for Hitachi Central Research Laboratory.