mindmap
root((KILO))
kilobyte
A unit of computer information equal to 1,024 bytes.
🌱A 200-word paragraph in the simplest text format takes up about a kilobyte of storage space on your hard drive. 🌳Knowing the root kilo-, you might think a kilobyte would be exactly 1,000 bytes. But actually a kilobyte represents the power of 2 that comes closest to 1,000: that is, 210 （2 to the 10th power）, or 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2, or 1,024. Why 2? Because the capacity of memory chips is always based on powers of 2. Locations in electronic memory circuits are identified by binary numbers （numbers that use only the digits 0 and 1）, so the number of addressable locations becomes a power of 2. kilometer A unit of length equal to 1,000 meters.
🌱U.S. highway signs near the Canadian border often show distances in kilometers in addition to miles. 🌳A kilometer is equal to about 62/100 of a mile, and a mile is equal to about 1.61 kilometers. The U.S. has been slow to adopt metric measures, which are used almost everywhere else in the world. Though our car speedometers are often marked in both miles and kilometers, the U.S. and Great Britain are practically the only developed nations that still show miles rather than kilometers on their road signs. But even in the U.S., footraces are usually measured in meters or kilometers, like the Olympic races. Runners normally abbreviate kilometer to K: "a 5K race" （3.1 miles）, "the 10K run" （6.2 miles）, and so on. kilohertz A unit of frequency equal to 1,000 cycles per second.
🌱A drone aircraft nosedived and crashed after an onboard tape recorder turned out to be using a 10-kilohertz signal, the same frequency used by the aircraft's control system. 🌳If your favorite AM radio station has a frequency of 680 kilohertz （kHz）, that means the station's transmitter is oscillating （vibrating） at a rate of 680,000 cycles per second （i.e., 680,000 times a second）. A related term is megahertz （MHz）, meaning "millions of cycles per second." Shortwave radio operates between 5.9 and 26.1 MHz, and the FM radio band operates between 88 and 108 MHz. Garage-door openers work at about 40 MHz, baby monitors work at 49 MHz, and so on. The terms hertz, kilohertz and megahertz honor the great German physicist Heinrich Hertz, the first person to broadcast and receive radio waves. kilogram A unit of weight equal to 1,000 grams.
🌱The kilogram is the only base unit of measurement still defined by a physical object rather than a physical constant （such as the speed of light）. 🌳The original concept of the kilogram, as the mass of a cubic decimeter of water （a bit more than a quart）, was adopted as the base unit of mass by the new revolutionary government of France in 1793. In 1875, in the Treaty of the Meter, 17 countries, including the U.S., adopted the French kilogram as an international standard. In 1889 a new international standard for the kilogram, a metal bar made of platinum iridium, was agreed to; President Benjamin Harrison officially received the 1-kilogram cylinder for the U.S. in 1890. But no one uses that bar very often; for all practical purposes, a kilogram equals 2.2 pounds.
🌱A 200-word paragraph in the simplest text format takes up about a kilobyte of storage space on your hard drive. 🌳Knowing the root kilo-, you might think a kilobyte would be exactly 1,000 bytes. But actually a kilobyte represents the power of 2 that comes closest to 1,000: that is, 210 （2 to the 10th power）, or 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2, or 1,024. Why 2? Because the capacity of memory chips is always based on powers of 2. Locations in electronic memory circuits are identified by binary numbers （numbers that use only the digits 0 and 1）, so the number of addressable locations becomes a power of 2. kilometer A unit of length equal to 1,000 meters.
🌱U.S. highway signs near the Canadian border often show distances in kilometers in addition to miles. 🌳A kilometer is equal to about 62/100 of a mile, and a mile is equal to about 1.61 kilometers. The U.S. has been slow to adopt metric measures, which are used almost everywhere else in the world. Though our car speedometers are often marked in both miles and kilometers, the U.S. and Great Britain are practically the only developed nations that still show miles rather than kilometers on their road signs. But even in the U.S., footraces are usually measured in meters or kilometers, like the Olympic races. Runners normally abbreviate kilometer to K: "a 5K race" （3.1 miles）, "the 10K run" （6.2 miles）, and so on. kilohertz A unit of frequency equal to 1,000 cycles per second.
🌱A drone aircraft nosedived and crashed after an onboard tape recorder turned out to be using a 10-kilohertz signal, the same frequency used by the aircraft's control system. 🌳If your favorite AM radio station has a frequency of 680 kilohertz （kHz）, that means the station's transmitter is oscillating （vibrating） at a rate of 680,000 cycles per second （i.e., 680,000 times a second）. A related term is megahertz （MHz）, meaning "millions of cycles per second." Shortwave radio operates between 5.9 and 26.1 MHz, and the FM radio band operates between 88 and 108 MHz. Garage-door openers work at about 40 MHz, baby monitors work at 49 MHz, and so on. The terms hertz, kilohertz and megahertz honor the great German physicist Heinrich Hertz, the first person to broadcast and receive radio waves. kilogram A unit of weight equal to 1,000 grams.
🌱The kilogram is the only base unit of measurement still defined by a physical object rather than a physical constant （such as the speed of light）. 🌳The original concept of the kilogram, as the mass of a cubic decimeter of water （a bit more than a quart）, was adopted as the base unit of mass by the new revolutionary government of France in 1793. In 1875, in the Treaty of the Meter, 17 countries, including the U.S., adopted the French kilogram as an international standard. In 1889 a new international standard for the kilogram, a metal bar made of platinum iridium, was agreed to; President Benjamin Harrison officially received the 1-kilogram cylinder for the U.S. in 1890. But no one uses that bar very often; for all practical purposes, a kilogram equals 2.2 pounds.
KILO is the French version of the Greek word chilioi, meaning "thousand." France is also where the metric system originated, in the years following the French Revolution. So in English, kilo- shows up chiefly in metric-system units. Before the computer age, the most familiar kilo- words for English-speakers were probably kilowatt, meaning "1,000 watts," and kilowatt-hour, meaning the amount of energy equal to one kilowatt over the course of an hour.🌸