Sophomore students from Occupational Therapy in De La Salle Health Sciences Institute had conducted an experiment concerning Archimedes’ Principle to determine the density of solids and liquids using Archimedes’ Principle. For the density of solids, they had made use of spring balance to measure the mass of the metal samples, which were tied via string, in air and when immersed inside a 2000mL beaker, where H2O lies. They had computed the density of each sample metal using the formula: ϱs = maϱw / ma – mw and computed a percentage error. As for the density of liquids, they had filled a graduated cylinder with 250mL liquid sample and had immersed a hydrometer. They had immersed a sample metal in the liquid sample and had measured its mass in air and beneath the liquid. They also had measured the volume of displaced liquid as the metal sample is immersed in the liquid and had computed the density using the formula: ϱL = WaWL / gV, and the percentage error after. They had been successful to support the theory of Archimedes and had came up with percentage error ranging from 5.76% to 9.91%.
Tradition tells us that the king was suspicious about the purity of the gold in his crown and asked Archimedes to find a way to determine if it was the real thing. Solving the problem seemed to be impossible because in those days (3rd century B.C.) nothing was known about chemical analysis. One day Archimedes was thinking about the problem while taking a bath. As he lay floating in the bathtub he thought about his “weightless” body. Suddenly he realized that all bodies “lose” a little weight when placed in water, and the bigger their volume, the more weight they lose. He realized that the density of a metal can be found from its weight and its weight loss in water. The weight of the King’s crown and its apparent loss of weight in water would tell him if it were made out of pure gold.
Archimedes shouted “Eureka!” (I have found it!) and rushed out into the street naked to announce that he had solved the problem. Today the effect he observed is called Archimedes’ Principle. Archimedes’ principle, principle that states that a body immersed in a fluid is buoyed up by a force equal to the weight of the displaced fluid. The principle applies to both floating and submerged bodies and to all fluids, i.e., liquids and gases. It explains not only the buoyancy of ships and other vessels in water but also the rise of a balloon in the air and the apparent loss of weight of objects underwater. Objectives:
1. To determine the density of solids using Archimedes’ Principle 2. To determine the density of liquids using hydrometer and Archimedes’s Principle
A. Density of Solids
B. Density of Liquids
* Human Error.
* Water properties. Water tends to cling to its container after it has been poured. The metals used to immerse in water had some attached water molecules on it causing the water inside the graduated cylinder to lessen.
In this experiment, the conductors was able to support Archimedes’ Principle: when an object is immersed in water, it feels lighter. Objects immersed in water, as shown in Results, gives of a lesser mass than if it’s hangging in the air. However, the density of solids and of liquids doesn’t change whether they are immersed in water or they are in the air. This experiment has supported that the density of an object can be determined by using its weight and its weight loss in the water, or the Archimedes’ Principle.
* Pearson Education. (2012). Infoplease. Archimede’s principle. Retrieved from http://www.infoplease.com/encyclopedia/science/archimedes-principle.html * Seely, O. Jr. (2000 March 21). Archimedes’ Principle. Density and
Archimedes’ Principle. Retrieved from http://www.csudh.edu/oliver/satcoll/archmede.htm