Fire - Pyrotechnology
Would early man be scared of fire?
Would he be running away from it?
Would he have then become familiar with the way it works? So now there would not be a need to simply run away. How do we find out?
Jill Pruetz, a primatologist has done some research on chimpanzees—our closest living relatives. He has found that chimps clearly understand the behavior of fire enough to have lost the fear of it that most animals typically possess. How different could we have been from them?
How does he know that chimpanzee are not afraid of fire?
Pruetz has observed chimps monitoring the progress of a passing wildfire from a few meters away and then moving in to forage in the burned-out area. So while chimps cannot build or contain fires, they understand how fire moves across the landscape, and they use this knowledge to their benefit
How many years could it have taken for man to move on from not being afraid to actually controlling fire? Controlling does not mean making fire ...
Long time...May be 20 lac years! Wow!
What kind of control over fire could man gain?
Probably man could capture fire, contain it, and supply it with fuel to keep it going within their living areas.
From where did he capture fire?
May be from Wildfires
70,000 and 40,000 years ago, a time of increasing cold as glaciers again spread across much of Europe
Quest for Fire - 1981 Movie
The story is set in Paleolithic Europe (80,000 years ago), with its plot surrounding the struggle for control of fire by early humans. No actual modern language nor subtitles were used.
In the movie, a tribe of cavemen possess fire in the form of a carefully guarded small flame which they use to start larger bonfires. The tribe is horrified when their fire is accidentally extinguished in a marsh. Because the tribe does not know how to create fire themselves, the tribal elder decides to send three men, on a quest to find fire.
How do we know that there was human controlled fire?
May be we could look for remains of fires at places where natural fires don't burn! About 4 lac year ago, a lot of such intact camp-fires (of charcoal and ash), have been found inside caves.
Interestingly the number of sites with such evidence increases dramatically
But could they make fire?
but whether they could make it remains an open question
Interesting Evidence! Layers and layers of Fire...
Within the same cave and old campfire ash was found underneath the new campfire ash. This could mean that the same cave was occupied by another community many years ago too. (around 1 lac years ago). And there is evidence of more use of fire in the older layers (1,00,000 years ago) and less use of fire in the newer layers (50,000 years ago). In fact Europe was very warm 1,00,000 years ago while it was much colder 50,000 years ago. Did man stop using fire?
How could it be that there was more fire back then when it was warmer? Isn't fire required more in cooler times?
This can make sense If we assume that the Neanderthals lacked the ability to start fire themselves and could thus only obtain it from natural fires, then we would expect to find much more evidence of fires during warmer periods and less during colder ones, because natural fires from lightning strikes occur much more frequently in warm conditions.
Does this mean that man survived in the coldest times without fire?
How could he? Could he make warm clothes? Was man very hairy back then? Could he eat uncooked meat? It is a mystery, because man in current form cannot think of surviving without fire.
Here are the beginnings of fire and engineering, the origins of pyrotechnology, and the bridge to more recent ceramic and metal technology
Scientists had been puzzled by the fine-grained and often reddish coloured silicate blades and axes excavated from prehistoric sites at Pinnacle Point on the South African coast. None of the material used to make these advanced tools matched local rocks (silcrete). The raw stone ''was just not suitable for tool production''.
Then a large flake of silcrete almost 10 centimetres in diameter was found embedded in ash in an ancient fire pit.
It was only at that moment the researchers began to suspect that the stone had been heat-treated.
Many of the tools had a sheen or gloss reminiscent of much later North American artefacts made from heated material.
To test the theory, the scientists recreated what ancient tool makers might have done by heating a pile of silcrete stone in a fire pit.
The next day the silcrete had become a deep red colour and was easily flaked. Using the heated stone, the researchers were able to produce realistic copies of silcrete tools.
The oldest evidence of pottery manufacture has been found at an archaeological site known as Odai Yamamoto, in Japan, where fragments from a specific vessel have been dated to about 16,500-14,920 years ago
THE INTRODUCTION OF POTTERY GENERALLY COINCIDES WITH THE ADOPTION OF AN AGRICULTURAL LIFESTYLE, WHEN DURABLE AND STRONG VESSELS AND CONTAINERS ARE NEEDED
Open firing techniques were used to produce the earliest pottery. Through this method, temperatures could range from about 600 to about 800-900 degrees
Closed Updraft kiln allows the heat to rise and the pottery is fired at a temperature level normally ranging from 1,000 to 1,200 degrees Celsius
In Ancient China, firing techniques allowed temperatures of about 1300-1400 degrees Celsius and even higher in some cases. At these temperatures, the mineral components of clay melt, resulting in a thin, translucent, white vitrified type of ceramic that is known as porcelain Not all types of clay can stand temperatures this high -- only some special types of clay which are largely free of impurities
What temperature the pots were exposed
By analysing the chemical composition of pottery fragments, it is possible to determine at what temperature the pottery was exposed, and therefore we can understand the level of technological sophistication of a society, at least in terms of their firing capabilities.
Man's first experiments with high temperature chemistry
Copper artefacts found in 8000 BC at sites located between Turkey to Iran
From ceramics to glass
For a long time the only way to make something hot was to burn some organic matter. Until the Middle Ages this was pretty much the remains of recently diseased organisms - wood, straw, dung. Burning the remains of organisms that died a long time ago like oil, coal, or peat was rarely done in the old times
Oxygen molecules (O2) from the air react with the carbon at the surface of the burning piece of material, forming CO2. Starting the reaction needs a certain amount of energy, and that's why you have to light a fire. However, whence the reaction starts, a lot of energy is released so that the balance is positive - forming CO2 releases more energy than needed to start the process. The net energy released is transferred to the various molecules around. The gas molecules then simply speed up compared to their average speed at room temperature
Burning pure carbon in air at best gives you Tmax » 2000 oC (3600 oF). Burning acetylene (C2H5) with pure oxygen gives you more energy and thus a higher Tmax - you can use that for welding or cutting steel. Well-dried hardwood contains around 50 % carbon and gives a Tmax » 1600 oC (2912 oF).
The energy production in your fire, or how much energy is produced per second (called "power"), is given by how much reactions of the type C + O2 Þ CO2 + energy take place per second.
This is obviously controlled by:
- The total surface area accessible. The burning reaction, after all, can only occur at the surface of something solid. That's why a number of small pieces of fuel produce more heat than just one solid lump of the same weight: they provide more surface area.
- The supply of oxygen. That's why blowing air on the burning surface, or through your bed of "coal" lumps, makes for more heat energy production. It does not raise the maximum temperature Tmax, however
- A fire in an open hearth rapidly distributes the energy produced in all directions; the temperature thus goes down rapidly with distance. That's why you need to suppress these losses by building a container around the fire in your hearth. And now we are talking furnaces or kilns.