Why Is It?

Why glue doesn’t stick to the inside of the tube?

Most glues contains agents called cure promoters, which cause glue to bond, and stabilizer, which stops it from sticking.  Inside the tube, the balance between cure promoters and stabilizers is like two peoples pulling on opposite ends of the rope.  The surface of the tube is specially formulated to be neutral so that the two agents remain balanced.  Once the glue is out of the tube, the stabilizers are overcome by moisture in the air and by contact with the surface you to stick, so the glue hardens and bonds.

Why horseshoes are considered lucky?

The belief comes from a sixteenth-century idea that iron horseshoes were protection against witches and evil.  John Aubrey, an Antiquarian writer wrote in his 1696 book Miscellanies that the reasoning was that Mars (the Roman god of war and associated with metal iron) was the enemy of Saturn (ruler of the witches).

Another interpretation of the superstition was that a horseshoe held in its side makes a “C” which stands for Christ.

Why are there jokers in packs of cards?

Jokers began life in a game called “Euchre” or “Joker” that became popular in America in the 1860’s and still played worldwide.  Euchre features two high-value cards, “bowers,” which are represented by two jacks of the same color.  They are beaten by the “best bower” or “joker”.

The new card posed a problem for manufacturers: the old 52-card packs could be printed on a single sheet of card in even rows and columns, but 53-cards packs couldn’t.  To combat this issue many manufacturer printed a second joker.  The tradition of having two jokers in each pack continues to this day.