The ancient Chinese accidently invented one of the most widely used weapons.  Alchemists in ancient China spend centuries trying to concoct an elixir of life with no success.  During the Tang Dynasty, an alchemist mixed 75 parts saltpetre with 14 parts charcoal and 11 parts sulfur, which exploded when it was exposed to an open flame.  

At first, China used gunpowder simply to scare or surprise their enemies.  When the Chinese realized the significance of what they had invented, they started to use gunpowder to kill instead.  The military forces of the Song Dynasty started using gunpowder devices against the Mongols as early as 904 A.D. The first of these devices was “flying fire”: an arrow with a burning tube of gunpowder attached to the shaft, primitive hand grenades, poisonous gas shells, flamethrowers and landmines.  By the 11th century, the Chinese were filling bombs with gunpowder and firing them from catapults. These fire cannons needed two people to carry them and were fired from moving platforms placed near the wall of the enemy city.

The Song government realized the extreme advantage they had in warfare and tried to keep gunpowder a secret from other countries.  In 1076, they even banned the sale of saltpeter to foreigners. Despite all their efforts, knowledge of this new substance was carried along the Silk Road to India, the Middle East, and Europe.  By 1280, recipes for gunpowder had been published in the west.

Gunpowder is just another example of how when a new technology is created, the rest of the world must either adapt or become obsolete.  This is extremely relevant when it comes to weapons and tools of warfare. If one civilization has better weapons, they will be able to conquer everyone else unless other civilizations learn the technology.  This is a constant cycle as civilizations create new technology while also trying to keep up with the new technology of others.

Additional Content:

http://www.monkeytree.org/silkroad/gunpowder/europe.html

Work Cited:

“Flying-cloud Thunderclap Eruptor.” depts.washington.edu/chinaciv/miltech/firearms.htm.

“Flying Fire.” ffden2.phys.uaf.edu/211.fall2000.web.projects/I.%20Brewster/History.html.

“Gun and Gunpowder.” Silk-Road, www.silk-road.com/artl/gun.shtml.

Ross, Cody. “Middle Age Technologies Gunpowder.” Four Rivers Charter, fourriverscharter.org/projects/Inventions/pages/china_gunpowder.htm.

Szczepanski, Kallie. “The Invention of Gunpowder: A History.” ThoughtCo, 23 Apr. 2018, www.thoughtco.com/invention-of-gunpowder-195160.

The Editors of Encyclopaedia Britannica. “Gunpowder Explosive.” Encyclopedia Britannica,www.britannica.com/technology/gunpowder.

Dendrochronology is a scientific method that uses the annual growth rings on trees to find out the exact year the tree was formed, which helps scientists date events, environmental change, and archaeological artifacts.  A tree’s rings start from the middle, with the oldest rings at the center of the tree and new growth occurring in a layer of cells near the bark. The rate at which the tree grows changes in a predictable pattern throughout the year due to seasonal climate changes, which causes visible growth rings.  Each ring on a tree represents a full year in the life of the tree.

Not only can these rings tell us how old a tree is, but each ring can show what the climate was like during that year.  In temperate climates, a tree will grow one ring each year. In the spring, there is more moisture, so the cells of a tree expand quickly.  In the summer, however, it becomes very dry and the tree cells start to shrink. When looking at tree rings, this change is cell size is visible and results in different sized widths of rings.  The rainier the year, the wider the ring and vice versa.

Not all trees are datable, due to factors such as natural tree variation and too much water, but about 40% of trees can be dated.  Simply counting the rings on a tree sample tells us how old the tree was when it was cut down, but to find out what time period the tree is from requires a little more work.  Scientists must look at the pattern of the rings, not just how many there are to find out the time period the tree is from. All trees in the same climate or region will have rings forming the same pattern, since a rainy year or a drought will affect all trees the same way.  To know if trees are from the same climate or region scientists must simply match the tree rings. This is possible, since tree ring patterns never repeat themselves, so they are specific to a time and place.

Skeleton Plotting: the graph paper is being marked where there are narrow rings

The process of identifying a pattern is not as complicated as it would seem.  Dendrochronologists lay a strip of graph paper on a sample of tree and mark where the narrow rings are.  This process is called Skeleton Plotting, since it is only marking the seasons of drought. It is easier to identify patterns by hand rather than by computer, because humans are so good at recognizing patterns.  Dendrochronologists will repeat this process for thousands of trees from the same region or climate to create a master pattern, which is called a master chronology.

Work Cited

Labeled Tree Sample. NASA, 25 Jan. 2017, climate.nasa.gov/news/2540/tree-rings-provide-snapshots-of-earths-past-climate/.

Mason, Matthew. “Dendrochronology: What Tree Rings Tell Us About Past and Present.” EnvironmentalScience, www.environmentalscience.org/dendrochronology-tree-rings-tell-us.

Skeleton Plotting. PBS, 30 Jan. 2013, www.pbs.org/time-team/experience-archaeology/dendrochronology/.

“Tree Ring Dating Dendrochronology.” PBS, 30 Jan. 2013, www.pbs.org/time-team/experience-archaeology/dendrochronology/.

Tree Sample. PBS, 30 Jan. 2013, www.pbs.org/time-team/experience-archaeology/dendrochronology/.

Additional Content

https://www.pbs.org/video/time-team-america-dendrochronology/