The laboratory experiment we did last time was Laboratory Exercise No. 8 which is “Determination of Buoyant Force Using Archimedes’ Principle”. In this experiment we performed the case that the object was partially submerged. We used a piece of wood coated with a wax so that the water will not be absorbed by the wood, and to make the result more accurate. In our fluid mechanics lecture the buoyant force of the object is equal to its weight. But in this experiment we are determining the buoyant force of the wood using Archimedes’ Principle. Using the beaker as our container for the liquid, we put a clay on its peak so that the water coming from it will not spill and also to collect all the water that will displaced by the wood by that we can lessen the error. It putting the peace of wood in the beaker, we should carefully put it so that the water will not splash that can cause error. The water that was displaced by the piece of wood was put in a graduated cylinder so that we can determine its volume. We can determine the weight of liquid in graduated cylinder or the liquid that was displaced from the beaker by the piece by subtracting the weight of graduated cylinder with water by the weight of cylinder alone. The weight of graduated cylinder with water is equal to 187 grams and the weight of cylinder is equal to 96.19 grams giving us a result of 90.81 grams as a weight of liquid, since it is in grams, and the needed unit in our laboratory experiment must be in Newton, we convert it first to kilograms by dividing it to 1000, and then multiply it to 9.81 to make it in to Newton and it is equal to 0.89 Newton and it is the weight of liquid displaced in the beaker by the piece of wood. The volume of the liquid that was displaced form the beaker by the piece of wood is equal to 92 cubic meter, the unit that we must use is in cubic meter so we divided it by 1000000 giving us a result of 0.000092 cubic meter. Using the volume of liquid and the given specific weight of water, we can compute now for the buoyant force of the wood, by simply multiplying the volume of liquid which is equal to 0.000092 cubic meter by the specific weight of 9700 N/m3 and the result is 0.8924. In finding the percent difference we must subtract the weight of water which is equal to 0.89 Newton by the buoyant force that is equal to 0.8924 divided by the weight of water multiplied by 100. We must use its absolute value or neglecting the negative sign since we’re talking about percentage, and the percentage error we got is 0.27 %, and the allowable percent that our professor said must be less that 2%, so our percent difference was accepted.
CONCLUSION
In this experiment which is determining the buoyant force using Archimedes’ Principle, the observer conclude that, the buoyant force of the object is equal to the weight of water that the object displaces.
