The Black Hawk War - Deception and Demise essays

The Black Hawk War - Deception and Demise essays The systematic slaughter of the Native Americans from the time of Columbus to the time of Roosevelt has often been compared to the holocaust of Jews in nazi Germany. Millions of Native Americans were brutally tortured and murdered by an invasion of foreign forces so as to steal their land and recourses (Churchill,126). Those who were not exterminated were forcefully removed from their land (either at gunpoint, the point of a bayonet or by forged treaties) and driven off to federal prison camps called reservations (source). In the early nineteenth century, whites started moving into what is now the state of Illinois. This movement precipitated numerous clashes with the Indians, including Black Hawks war. The defeat of Black Hawk removed a large obstacle to white settlement in the Old Northwest. In 1803, an exploratory push by Lt. Zebulon Pike, an American explorer, into the upper Mississippi valley signified the end of an era for the Sauks and their allies, the Foxes. The Indians debated whether to accommodate or resist the advance of the whites frontier. One group, headed by Keokuk, a Sauk, argued for accommodation, but Black Hawk, another Sauk leader, fiercely opposed such a policy. Black Hawks convictions were confirmed in 1804, when white settlers convinced the Sauk and Fox Indians to sign a treaty decreeing that they move west of the Mississippi. The treaty had no real claim to validity and was hardly understood by the Native Americans. Some refused, however, and soon after the War of 1812, Black Hawk denounced the treaty and proclaimed the Indians determination to retain their land. The next decade witnessed a steady decline in the fortunes of the Sauks and the Foxes. White population pressures forced the Indians to adhere to the treaty of 1804 and abandon their old territory. By the end of the 1820s, all had been forcibly removed and the lands sold by the state at public auction. Despite th...

Specific Gravity - Definition of Specific Gravity

Specific Gravity - Definition of Specific Gravity The specific gravity of a substance is the ratio of its density to a specified reference substance. This ratio is a pure number, containing no units. If the specific gravity ratio for a given substance is less than 1, that means the material will float in the reference substance. When the specific gravity ratio for a given material is greater than 1, that means the material will sink in the reference substance. This is related to the concept of buoyancy. The iceberg floats in the ocean (as in the picture) because its specific gravity in reference to the water is less than 1. This rising vs. sinking phenomenon is the reason that the term specific gravity is applied, although gravity itself plays no significant role in this process. Even in a substantially different gravitational field, the density relationships would be unchanged. For this reason, it would be far better to apply the term relative density between two substances, but for historical reasons, the term specific gravity has stuck around. Specific Gravity for Fluids For fluids, the reference substance is usually the water, with a density of  1.00 x 103 kg/m3  at 4 degrees Celsius (waters densest temperature), used to determine whether or not the fluid will sink or float in water. In homework, this is usually assumed to be the reference substance when working with liquids. Specific Gravity for Gases For gases, the reference substance is usually normal air at room temperature, which has a density of approximately 1.20 kg/m3. In homework, if the reference substance is not specified for a specific gravity problem, it is usually safe to assume that you are using this as your reference substance. Equations for Specific Gravity The specific gravity (SG) is a ratio of the density of the substance of interest (Ï i) to the density of the reference substance (Ï r). (Note: The Greek symbol rho, Ï , is commonly used to represent density.) That can be determined using the following formula: SG Ï i à · Ï r Ï i / Ï r Now, considering that the density is calculated from mass and volume through the equation Ï  m/V, this means that if you took two substances of the same volume, the SG could be rewritten as a ratio of their individual masses: SG Ï i / Ï rSG mi/V / mr/VSG mi / mr And, since the weight W mg, that leads to a formula written as a ratio of weights: SG mi / mrSG mig / mrgSG Wi / Wr It is important to remember that this equation only works with our earlier assumption that the volume of the two substances is equal, so when we talk about the weights of the two substances in this last equation, it is the weight of equal volumes of the two substances. So if we wanted to find out the specific gravity of ethanol to water, and we know the weight of one gallon of water, then we would need to know the weight of one gallon of ethanol to complete the calculation. Or, alternately, if we knew the specific gravity of ethanol to water, and knew the weight of one gallon of water, we could use this last formula to find the weight of one gallon of ethanol. (And, knowing that, we could use it to find the weight of another volume of ethanol by converting. These are the sorts of tricks that you may well find among homework problems that incorporate these concepts.) Applications of Specific Gravity Specific gravity is a concept that shows up in a variety of industrial applications, particularly as it relates to fluid dynamics. For example, if youve ever taken your car in for service and the mechanic showed you how small plastic balls floated in your transmission fluid, youve seen specific gravity in action. Depending on the specific application in question, those industries may use the concept with a different reference substance than water or air. The earlier assumptions applied only to homework. When you are working on a real project, you should know for sure what your specific gravity is in reference to, and shouldnt have to make assumptions about it.