Measuring the Viscosity of a Liquid

Measuring the Viscosity of a Liquid

Aim

The aim of this experiment is to find out how fluid Bath Oils really

are by measuring its viscosity.

Plan

The first thing that I'll do is to measure the spheres volume by first

measuring its radius. I will then, by calculating the spheres mass, be

able to calculate the density of the sphere. This will be used later

when calculating the viscosity of the bath oil. I will then find the

density of the bath oil, also used during calculations later on. Next

I will fill a cylinder with liquid about 5cm from the top to allow for

the liquid to rise as the sphere enters the cylinder. This will be

left to allow any air bubbles caught during pouring to escape. This

will be clamped to the workbench before I check that the tube is

straight using a spirit level. I will then mark, with tape, a starting

point to start measuring from, on the cylinder, about another 5-10cm

below the surface of the liquid, (this will allow the sphere to reach

terminal velocity before I begin to make measurements). I will measure

from the top of the tape every time to make sure that the test is

fair. I will mark, with tape, an ending point on the cylinder, about

5cm from the bottom. I will again measure from the top of this tape

every time. Now that I have my two points I will measure the distance

between them, using the top of both tapes, to find my "fall distance"

used in later calculations. I will then hold a sphere so that it is

just touching the liquid whilst ready with a stop-clock to measure the

time. I will then release the ball and begin timing when the sphere

crosses the top of the start tape and stop the clock when is crosses

the top of the end tape. I will repeat this for 5 different size

spheres and repeat the experiment for each sphere 3 times and then