Design of experiments
The experiments conducted in accord with the scientific method have several features in common. The design of experiments attempts to balance the requirements and limitations of the field of science in which one works so that the experiment can provide the best conclusion about the hypothesis being tested.
In some sciences, such as physics and chemistry, it is relatively easy to meet the requirements that all measurements be made objectively, and that all conditions can be kept controlled across experimental trials. On the other hand, in other cases such as biology, and medicine, it is often hard to ensure that the conditions of an experiment are performed consistently; and in the social sciences, it may even be difficult to determine a method for measuring the outcomes of an experiment in an objective manner.
For this reason, sciences such as physics and several other fields of natural science are sometimes informally referred to as "hard sciences", while social sciences are sometimes informally referred to as "soft sciences"; in an attempt to capture the idea that objective measurements are often far easier in the former, and far more difficult in the latter.
Tuesday, December 26, 2006
Monday, December 18, 2006
Sinkhole
Sinkholes, also known as sinks, shakeholes or dolina, and cenotes, are formed by the collapse of cave roofs and are a feature of landscapes that are based on limestone bedrock. The result is a depression in the surface topography. This may range anywhere from a small, gentle earth-lined depression, to a large, cliff-lined chasm. Most often there is a small area of rock exposure near or at the bottom of a sinkhole, and a patent opening into the cave below may or may not be visible. In the case of exceptionally large sinkholes, such as Cedar Sink at Mammoth Cave National Park, there may actually be a stream or river flowing into the bottom of the sink from one side and out the other side.
Sinkholes often form in low areas where they form drainage outlets for a closed local surface drainage basin. They may also form in currently high and dry locations. Florida has been known for having frequent sinkholes, especially in the central part of the state.
Sinkholes, also known as sinks, shakeholes or dolina, and cenotes, are formed by the collapse of cave roofs and are a feature of landscapes that are based on limestone bedrock. The result is a depression in the surface topography. This may range anywhere from a small, gentle earth-lined depression, to a large, cliff-lined chasm. Most often there is a small area of rock exposure near or at the bottom of a sinkhole, and a patent opening into the cave below may or may not be visible. In the case of exceptionally large sinkholes, such as Cedar Sink at Mammoth Cave National Park, there may actually be a stream or river flowing into the bottom of the sink from one side and out the other side.
Sinkholes often form in low areas where they form drainage outlets for a closed local surface drainage basin. They may also form in currently high and dry locations. Florida has been known for having frequent sinkholes, especially in the central part of the state.
Wednesday, December 13, 2006
Temple at Uppsala
The Temple at Uppsala was a semi-legendary cultic site in Gamla Uppsala, near modern Uppsala, Sweden, that was formed to worship the Norse gods of prehistoric times. The temple is sparsely recognized, but it is referenced in the Norse sagas and Saxo Grammaticus' Gesta Danorum. It is also described by Adam of Bremen. These images might, however, be influenced and biased by the Biblical stories and recollections of the Ancient Roman temples.
The chief controversies regarding the temple focus specifically on determining where in Old Uppsala the temple was located and whether or not it was a building. Some believe that the temple was puzzled with the hall of the Swedish kings. Churches were usually built and consecrated on top of older pagan temples and other sites that witnessed ritual behavior. During an excavation of the present church, the remains of one, and possibly several, large wooden buildings were found beneath the church's foundation.Snorri Sturluson wrote that the temple had been built by the god Freyr, who allegedly used to reside at Uppsala. Snorri and Saxo Grammaticus both claimed that it was Freyr who began the tradition of human sacrifices at the temple site. The Norse sagas, Saxo Grammaticus and Adam of Bremen describe the sacrifices at Uppsala as popular festivals that attracted people from all over Sweden. Many of these sources provide accounts of human sacrifice for the Norse gods.
The Temple at Uppsala was a semi-legendary cultic site in Gamla Uppsala, near modern Uppsala, Sweden, that was formed to worship the Norse gods of prehistoric times. The temple is sparsely recognized, but it is referenced in the Norse sagas and Saxo Grammaticus' Gesta Danorum. It is also described by Adam of Bremen. These images might, however, be influenced and biased by the Biblical stories and recollections of the Ancient Roman temples.
The chief controversies regarding the temple focus specifically on determining where in Old Uppsala the temple was located and whether or not it was a building. Some believe that the temple was puzzled with the hall of the Swedish kings. Churches were usually built and consecrated on top of older pagan temples and other sites that witnessed ritual behavior. During an excavation of the present church, the remains of one, and possibly several, large wooden buildings were found beneath the church's foundation.Snorri Sturluson wrote that the temple had been built by the god Freyr, who allegedly used to reside at Uppsala. Snorri and Saxo Grammaticus both claimed that it was Freyr who began the tradition of human sacrifices at the temple site. The Norse sagas, Saxo Grammaticus and Adam of Bremen describe the sacrifices at Uppsala as popular festivals that attracted people from all over Sweden. Many of these sources provide accounts of human sacrifice for the Norse gods.
Monday, November 27, 2006
Nylon
The real star of the plastics business in the 1930s was "polyamide" (PA), far better known by its trade name, "nylon". Nylon was the first entirely synthetic fiber, introduced by
Du Pont Corporation at the 1939 World's Fair in New York City.
In 1927, Du Pont had begun a secret expansion project designated "Fiber66", under the way of a Harvard chemists Wallace Carothers and Chemistry Department director E.K. Bolton. Carothers had been hired to carry out pure research, and not only investigated new materials, but worked to recognize their molecular structure and how it related to fabric properties. He took some of the first steps on the road to "molecular design" of materials.
His work led to the detection of synthetic nylon fiber, which was very powerful but also very elastic. The first submission was for bristles for toothbrushes. However, Du Pont's real target was silk, mainly silk stockings.
The real star of the plastics business in the 1930s was "polyamide" (PA), far better known by its trade name, "nylon". Nylon was the first entirely synthetic fiber, introduced by
Du Pont Corporation at the 1939 World's Fair in New York City.
In 1927, Du Pont had begun a secret expansion project designated "Fiber66", under the way of a Harvard chemists Wallace Carothers and Chemistry Department director E.K. Bolton. Carothers had been hired to carry out pure research, and not only investigated new materials, but worked to recognize their molecular structure and how it related to fabric properties. He took some of the first steps on the road to "molecular design" of materials.
His work led to the detection of synthetic nylon fiber, which was very powerful but also very elastic. The first submission was for bristles for toothbrushes. However, Du Pont's real target was silk, mainly silk stockings.
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