Objective:
The experiment is
designed to measure the buoyant force experimentally on an object under the
water and use different to measure and verify the answer.
Procedures:
1. Measure the weight of the metal cylinder before and after submerging
it in water.
2.
Draw the FBD of the metal in the water;
determine the relationship between all the forces. Use the relation to
calculate buoyant force.
3.
Using water displacement method to
measure the volume and calculate for the buoyant force.
4.
Directly measure the volume of the
cylinder and calculate for the buoyant force.
Results:
Value obtained:
1.
Weighing method:
FBD:
Thus, Fbuoyant = mg –
T
Mg = 1.1540 N T = 0.7766 N Thus Fbuoyant = 0.3774 N
2.
Water displacement:
Mass of dry
beaker: 143.60 g Mass of beaker
& water: 181.33 g
Thus water
mass is 37.73 g Thus Fbuoyant =
37.73 / 1000 x 9.8 = 0.3698 N
3.
Volume of cylinder:
Height: 6.91
cm Diameter: 2.55 cm Thus volume is
V = h x (d/2)2
x π = 35.27 mL
Thus Fbuoyant =
0.3456 N
The three methods yield buoyant force as 0.3774 N, 0.3698
N, and 0.3456 N.
Average
force is 0.3643 N; percent standard deviation is 4.559 %.
Discussion:
The data has a percent standard deviation less than 5 %, thus the
result is good. The buoyant force is 0.3456 N in this lab and the error may
results from water evaporation, imprecise measurement in water displacement and
the quality of force sensor.
