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Lab Report on Archimedes’ Principle Theoretically, density, or rather specific density of parent material determines whether an object sinks or floats when immersed in water. Specific gravity is the ration of a material’s density to that of water. Practically, the physical properties of volume, density, and mass are related as d = m/v. Experiments that study the floating and sinking properties of different materials are practical application of Archimedes Principle (Smith 15). According to the principle, volume of liquid displaced when an object is immersed in water is directly related to the weight of the immersed object.
Below are tabulated results indicating numerous physical properties of different materials determined through a typical Archimedes Principle experiment.ObjectMass (g) [+/-0.5 g]Volume (m3) [+/- 1 × 10-9 m3]Density (kg/m3) [+/- 1×106 kg/m3]Weight (N) [+/- 0.1 N]Apparent Weight (N) [+/- 0.01 N]Specific Gravity[+/- 0.01]Metal Cylinder59.59.35645 ×10-96.35925 ×106583.1573.124.03Irregular Object61.52.36844 ×10-82.59665 ×106 602.7514.503.48Wooden Block24.57.27457 ×10-83.36789 ×105 240.1194.800.93 Post Lab QuestionsQuestion 1aAdmittedly, both weight and density are physical properties of matter.
Density is calculated by finding the ratio of a material’s mass to that of the material’s volume. Contrarily, weight is the mass of a material in a particular gravitational field. In the calculations, weight was obtained when mass was multiplied by 9.98; the earth’s acceleration due to gravity. In this context, I believe that weight is a variable property which changes with a corresponding change in the external force of gravitational acceleration. However, density is a rather static variable in matter.
Density is derived from the unchanging parameters of mass and volume. On the other hand, weight is derived from the unchanging parameter of mass and the changing parameter of gravitational acceleration (Smith 28). Therefore, the experiment’s computations indicate that density describes a material more accurately than weight. Question 1bWhen an object is suspended in air, gravity is the only major force acting on that object. However, an object immersed in water is acted upon by two major forces; gravity, and buoyant force.
Gravity pulls an immersed object down while buoyant force pushes the immersed object upwards. Consequently, a portion of the object’s actual weight is neutralized by the upward force of buoyancy, thus causing an immersed object to weigh less (Smith 31). Technically, an object does not lose the same amount of weight when immersed in a liquid other than water. First, water and other liquids have different densities. Buoyancy of objects is determined by the ration of an object’s density to that of the reference liquid.
Since buoyant forces determine the weight of an immersed object, then the magnitude of buoyant forces acting on a water-immersed object are not necessarily equal to the magnitude of buoyancy experienced by the same body immersed in a different liquid (Smith 34). Source of ErrorsPossibly, uncertainties of the tabulated values were caused by either random or systematic experimental errors. Instrument resolution was probably the leading cause of random errors in the experiment’s instrumental readings.
Mass measuring scales and Vanier calipers cannot facilitate acquisition of precise measurements smaller than 0.1 g and 0.5 mm respectively. The limited resolution of these quantity measuring instruments limits the ability to obtain small but significant measurements (Smith 47). Another possible cause of errors in the experiment was parallax. Parallax is a systematic error associated with the effects of scale pointer or observer’s eye in obtaining readings. For example, obtaining readings from the Vanier calipers requires that the observer’s eyes be aligned squarely with the caliper’s pointer.
Failure to achieve the required alignment with the instrument’s scale yields either high or low readings. Work CitedSmith, Dennis. Archimedes: Archimedes’ Principle and the Law of Flotation. Pittsburg: John Wiley & Sons, 2012. Print.
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