Scientrics

On August 10, 2006, authorities in Great Britain announced that they had arrested several people in connection with a plot to attack airplanes with liquid explosives. The attackers planned to disguise the explosives as ordinary liquids and smuggle them aboard. For this reason, authorities in both the United States and Great Britain warned all passengers that liquids would not be allowed in carry-on luggage until the crisis passed. The ban on liquids included hair spray, shampoo and beverages -- items people travel with all the time. AP Photo/Kevin Wolf A trash container overflows with water bottles and other liquid items near the security checkpoint at Dulles Airport on August 10, 2006, in Chantilly, Va. So what exactly are liquid explosives, and what do they do? Most explosives work in basically the same way. They burn or decompose very quickly, producing lots of heat and gas, which rapidly expands and can tear things apart. Usually, an explosive material requires some kind...

Mayan mathematical system-1-20 Mayan Numbers and Math Along with their advances to the calendar -- like the Tzolk'in, the Haab, and the Long Count -- the Mayans also created their own math system. They used a series of dots and bars to signify numbers. One dot equaled one unit while one bar equaled five units. A shell symbol signified zero. In a system similar to the one we use now, the Mayans used place values to designate large numbers. However, the similarities end there. Mayan math - 27Mayan math - 29 Their place values are vertical, where ours are horizontal. For instance, we write the number 27 horizontally -- the number 2, then the number 7 to the right of it. The Mayans, however, would write 27 vertical­ly -- their symbol for 7 (a line with 2 dots over it) would be on the bottom, and the symbol for 20 (a dot on the line above) would be directly over it. The same applies for other numbers, like 29.

The Long Count Calendar Topical Press Agency/ Getty Images A Mayan calendar column was found in Quirigua, Yucatan peninsula, Mexico, on August 13, 1929. Unfortunately, the Long Count calendar isn't as simple as combining two calendars together to get new dates. It'­s a little more complicated and abstract. In order to understand the Long Count, you first need to become familiar with a few terms: One day - kin 20 days - uinal 360 days - tun 7,200 days - katun 144,000 days - baktun The span of the Long Count calendar is called the Great Cycle , and lasts approximately 5,125.36 years [source: Jenkins ]. To find the Lon­g Count date that corresponds with any Gregorian date, you'll need to count the days from the beginning of the last Great Cycle. But determining when the last cycle began and matching that up to a Gregorian date is quite a feat. English anthropologist Sir Eric Thompson set out to determine the date, and he looked to the Spani...

The Haab Calendar and the Calendar Round mayan calendar in stoneThe Haab calendar is very similar to the Gregorian calendar that we use today. It's based on the cycle of the sun, and was used for agricultural, economic and accounting activities. Much like the Tzolk'in calendar, it's also comprised of uinals, and each day has its own hieroglyph and number. However, instead of using 13 uinals for 260 days, the Haab calendar has 18 uinals, giving it 360 days. Astronomers noticed that 360 days wasn't enough time for the sun to make it through a full solar cycle. They argued that the calendar should follow the cycle as closely as it could in order to be as accurate as possible. However, Mayan mathematicians didn't see it that way. They wanted to keep things simple, in increments of 20, just like their math system. The astronomers and mathematicians finally agreed on the 18 uinals, with five "nameless days" called the wayeb [source: The Maya Calendar]. The wa...

The Tzolk'in Calendar The Tzolk'in calendar was the first one used by the Mayans . Most calendars used throughout Mesoamerica consisted of 260 days. The Tzolk'in, or Sacred Round, calendar followed suit. One theory for its length is that 260 days is the length of pregnancy , and the calendar was based on that [source: Maya Mystery School ]. Another states that it was the length of time to cultivate corn. It's more likely that it was based on numbers. Numbers had great significance in the Mayan culture. For example, the number 20 signifies the number of digits a person has -- 10 fingers and 10 toes. The number 13 refers to the major joints in the human body where it's believed disease and illness enter and attack -- one neck, two shoulders, two elbows, two wrists, two hips, two knees and two ankles [source: Garcia ]. The number 13 also represented the levels of heaven where sacred lords ruled the Earth [source: Tzolk'in Calendar ]. It's these numbe...

A traditional Mayan calendar Most people around the globe look at some form of a calendar every single day. ­Business executives check to see when their meetings are scheduled. The busy mom confirms soccer practices and piano lessons. College students ensure that their papers are turned in on time and they have plenty of time to study for their history exams. For the people of ancient Maya, calendars were just as important to daily life as they are to people today. In this article, we'll look at how the Mayan calendar came to be and the meaning behind each type of calendar the Mayans created. First, let's get a little background on the Mayans. The Mayans originated in a region called Mesoamerica , or Middle America. This region lies in between Mexico and South America and was home to many other cultures, including the Aztec , Olmec, Teotihuacan and Toltec. The Mayans lived in what are today's Guatemala , Belize , Honduras , El Salvador and Southern Me...