A "pica" is a unit of measurement commonly used in typography and desktop publishing to represent the size of text, fonts, and other elements on a printed page. The pica is part of a system of measurement used in the field of typesetting, which involves arranging and designing text for printed materials.
In the pica system:
1 pica (abbreviated as "p") is equal to 12 points. 1 point (abbreviated as "pt") is approximately equal to 1/72nd of an inch.
So, 1 pica is roughly equal to 1/6th of an inch.
This system is based on the traditional point system used in printing, where a point is a very small unit of measurement. Picas and points are still widely used in the design and printing industry, especially when specifying font sizes, line spacing, and other layout details for printed materials like books, magazines, and newspapers.
In digital design and modern desktop publishing software, you can often switch between using picas and points or other units like inches, millimeters, or pixels to set and adjust the layout of text and graphic elements.
An "angstrom" (symbol: Å) is a unit of length that is commonly used in the field of nanotechnology, molecular biology, and atomic-scale physics and chemistry. It is named after the Swedish physicist Anders Jonas Ångström, who made significant contributions to the study of spectroscopy and the understanding of atomic and molecular structure.
One angstrom is equal to 0.1 nanometers (nm) or 1 × 10^-10 meters (m). In other words, it is a very small unit of length, often used to describe the size of atoms, molecules, and the wavelengths of electromagnetic radiation such as X-rays and gamma rays.
The angstrom is particularly useful when dealing with structures at the atomic and molecular scale, where measurements are often in the range of a few angstroms. For example, the diameter of a hydrogen atom is about 0.1 angstroms, and the bond length between two carbon atoms in a molecule like benzene is approximately 1.4 angstroms.