Experiment 3 Buoyant Force and Archimedes Principle In this experiment you will investigate the effect fluids have of the weight of submerged objects Materials 1 250 mL Beaker 1 Catch Pan 1 100 mL Graduated Cylinder 1 250 g Hanging Mass 1 6 Rubber Stopper 5 N Spring Scale Short String Vernier Caliper Paper Towels Water You Must Provide Procedure 1 Use the Vernier caliper to measure the diameter and height of the 250 g hanging mass Record the values in Table 2 2 Place the 250 mL beaker on the catch pan 3 Fill a 250 mL beaker to the brim with water Be careful not to spill any water in the catch pan If water does spill use a paper towel to clean it up and make sure the beaker is completely full of water 4 Tie one end of a string to the 250 g hanging mass and the other end to the spring scale Suspend the hanging mass in air and record its weight in Table 3 5 Slowly submerge the hanging mass under water being careful not to let the hanging mass touch the sides or bottom of the beaker The water will overflow into the catch pan 6 Try to keep your hand as stable as possible to keep the hanging mass stationary in the water Record the weight of the mass in water in Table 3 7 Slowly raise the mass out of the water Be sure not to spill any extra water into the catch pan Set the hanging mass down away from the catch pan and remove the beaker from the catch pan 8 Carefully pour the water into the 100 mL graduated cylinder and record the volume of displaced water Dry off the catch pan to be used again 9 Repeat Steps 2 8 for the rubber stopper 2014 eScience Labs LLC All Rights Reserved Table 2 Dimensions of 250 g Hanging Mass Diameter cm Height cm 1 5 5 5 Table 3 250 g Hanging Mass Buoyancy Data Object Weight in Air N Weight in Water N Buoyancy Force N Volume Displaced mL 250 g Hanging Mass 3 1 N 2 6 N 05 65 mL Rubber Stopper 3 N 1N 0784 8 mL Post Lab Questions 1 What happens to the apparent weight when the objects are submerged in water The apparent weight is the true weight minus the buoyant force It is less than the true weight hence we can say that it decreases 2 Use the value of the buoyant force to calculate an experimental value of the volume of all of the objects in kg m3 Fb LVD g Show your work 250 g mass 0 05 1000 V 9 8 V 0 05 9800 V 5 102 x 10 6 m 3 3 Use the measured dimensions of the 250 g mass to calculate the volume of the mass Show your work V A h V 0 015 2 0 055 1 24 10 5 m 3 2014 eScience Labs LLC All Rights Reserved 4 Determine the percent difference between the measured volume of the cylinder and the value calculated from the buoyant force measurement Show your work difference 1 24 x 10 5 5 102 x 10 6 5 102 x 10 6 1 43 5 Using the fact that 1 mL 1 x 10 6 m3 compare the volume of the displaced water to the calculated volume of the mass from Post Lab Question 3 with a percent difference calculation Show your work Volume of displace water as given Calculate volume of mass 12 4 Percentage error 424 19 6 Are the experimental values of the volume of the 250 g mass from Archimedes Principle larger or smaller than the calculated value using the caliper measurements Why Which of the three values for volume is more accurate Which of the two experimental volumes are more accurate Explain Experimental value 5 102 Measured value 12 4 Experimental value is much smaller than the measured volume Value taken by direct measurement is more correct because it is not obtained by interpreting other concepts or principle it is directly taken from instrument Among the two experimental values direct measurement value is more correct 7 Use the true weight and experimental volume of the rubber stopper to calculate the density of the cylinder Show your work 2014 eScience Labs LLC All Rights Reserved 8 Look up the density of rubber and compare your measured value of the density with the values listed Density of rubber 1200 kg m 3 9 Does the data support Archimedes Principle Why or why not Yes the data must be in agreement with the Archimedes principle The reason why a buoyant forces acts upwards on an object that is submerged in water is because the object s weight is pushing it downwards This is scientifically called displacing 10 Identify two possible sources of error in the experiment How could the procedure be revised to remove these potential errors 2014 eScience Labs LLC All Rights Reserved
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