The first one.......

The paper clip was invented in 1899 or 1890 by a Norwegian patent clerk called Johann Vaaler. His original paper clip was a thin spring-steel wire with triangular or square ends and two "tongues." Vaaler patented his invention in Germany and later in the USA (1901). The modern-shaped paper clip was patented in April 27, 1899 by William Middlebrook of Waterbury, Connecticut, USA.

The steam engine was invented by Heron, an ancient Greek geometer and engineer from Alexandria. Heron lived during the first century AD and is sometimes called Hero. Heron made the steam engine as a toy, and called his device "aeolipile," which means "wind ball" in Greek. The steam was supplied by a sealed pot filled with water and placed over a fire. Two tubes came up from the pot, letting the steam flow into a spherical ball of metal. The metallic sphere had two curved outlet tubes, which vented steam. As the steam went through the series of tubes, the metal sphere rotated. The Greeks never used this remarkable device for anything but a novelty. A steam engine designed for real work wasn't designed until 1690, when Dionysius Papin published plans for a for a high-pressure steam engine. Thomas Savery built the first steam engine in 1698. Watt later improved the steam engine.

Safety matches were invented by Johan Edvard Lundstrom of Sweden in 1855. Lundstrom's new match was the first simple and safe way to make a fire. His new safety match could only be lit by striking the match against the specially-prepared surface that came attached to the box. Lundstrom put red phosphorus on the rough striking paper (on the outside the match box); the other fire-starting chemicals were on the match's head. Previous matches gave long-time users an ailment called "phossy jaw;" this was a painful and deadly disease caused by the older matchs' yellow phosphorus that ate into the users' jaws.

Radar is short for RAdio Detection And Ranging. Radar is used to locate distant objects by sending out radio waves and analyzing the echoes that return. Radar can determine where a distant object is, how big it is, what shape it has, how fast it's moving and in which direction it's going. Radar is now used to watch developing weather patterns, to monitor air traffic, to track ships at sea, and to detect missiles.
The first practical radar system was invented in 1935 by the Scottish physicist Sir Robert Alexander Watson-Watt (April 13, 1892-December 5, 1973). He developed radar to help track storms in order to keep aircraft safe. His invention eventually helped the allies win World War 2 against the Germans.

A hot-air balloon is a balloon that is filled with hot air; it rises because hot air is less dense (lighter) than the rest of the air. Joseph and Jacques Etienne Montgolfier were two French brothers who made the first successful hot-air balloon. Their first balloon was launched in December, 1782, and ascended to an altitude of 985 ft (300 m). This type of hot-air balloon was called the Montgolfier; it was made of paper and used air heated by burning wool and moist straw. The first passengers in a hot-air balloon were a rooster, a sheep, and a duck, whom the Montgolfier brothers sent up to an altitude of 1,640 ft (500 m) on September 19, 1783 (the trip lasted for 8 minutes); the animals survived the landing. This event was observed by King Louis XVI and Queen Marie Antoinette of France.

Hi ladies and gentlemen, our today’s post is going to be about Geiger-Muller counter. The Geiger counter (sometimes called the Geiger-Muller counter) is a device that detects ionizing radioactivity (including gamma rays and X-rays) - it counts the radioactive particle that passes through the device. The German nuclear physicist Hans Wilhelm Geiger developed the device from 1908-12. At that time, Geiger was an assistant to the British physicist Ernest Rutherford (1871-1937). In 1928, the Geiger counter was improved by the German physicist E. Walther Muller.
Thus I think that this post will be helpful for u to know about Geiger-Muller counter. See you in next post with more info…