Since the mass of the ball bearing used in this experiment was very light, 20 balls were measured and the result was divided by 20 for better accuracy. This procedure was repeated for the sizes and the results are as follows:
Diameter (mm) Mass (kg)
2 0.04
3 0.075
4 0.11
To find out the densities of the three balls, the following formula was used:
Density= (mass of the ball)/(Volume of the ball)= mass/(4/3 π r^3 )
Density of 2mm ball = (0.04⁄1000)/(4/3 π 〖(0.001)〗^3 )=9551 kg/m^3
Density of 3 mm ball = (0.075⁄1000)/(4/3 π 〖(0.0015)〗^3 )=5305.16 kg/m^3
Density of 3 mm ball = (0.11⁄1000)/(4/3 π 〖(0.0020)〗^3 )=3282.57 kg/m^3
Accordingly, the average density of the three balls is:
Avarage Density= (9551+5305.16+3282.57)/3
Avarage density=6046.24 kg/m^3
The above result is summarized as follows:
Diameter (mm) Density (kg/m^3) Average Density (kg/m^3)
2 9551
6046.24
3 5305.16
4 3282.57
Castrol oil results:
Density of the liquid Castrol was found by dividing its mass over its volume at temperature of 26℃ as follows:
Density= (mass of the liquid)/(Volume of the liquid used) Density of liquid= mass/volume= (24.5g )/(25 ml)= 0.98 g⁄ml
=980 kg/m^3
The three balls were dropped into the liquid containing Castrol oil at a known distance of 0.252 m and the following data were recorded:
Castor oil
Travelling Distance = 25.2 cm (0.252m) Time in seconds Diameter 1 2 3 4 5 6 Average
Time (s) Velocity m/sec
2mm 1.62 1.54 1.60 1.63 1.55 1.78 1.62 0.155
3mm 1.10 1.15 1.11 1.19 1.20 0.97 1.12 0.225
4mm 0.89 0.86 0.84 0.82 0.81 0.88 0.85 0.296
Six trials were conducted to measure the time for the ball to reach to the bottom of the container. The following is a sample calculation done for 2 mm diameter. The Average time for (2mm) ball =(1.62+1.54+1.60+1.63+1.55+1.78)/6=1.62 sec
Terminal Velocity = Distance/(Time (avarge) ) = (0.252 m)/(1.62 s) =0.155 m/s
Accordingly, viscosity was