Apparatus
Clamp, Clamp stand, Glass tube, Ball bearing, Bunsen burner, Tripod, Gauze, Water, 250ml beaker, Stopwatch, Thermometer, C6, C8, C10, C12, and C16 oils.
Diagram
Preliminary Diagram
Preliminary Work
My preliminary work helped me significantly to write my plan. Through trying to carry out some practice tests, I found that it was hard and not particularly accurate if I just picked up the ball bearing and dropped it from a little bit above the tube because then my results will be inaccurate. This is why I decided to drop the ball bearing from the rim of the glass tube. This meant it would always be the same force being put on the ball bearing. My preliminary work has also helped me to determine what the angle the tube should be at. The reason I chose to have the tube at 35º to the tabletop was that at 90º the ball bearing fell much too fast making it difficult to measure the time. However at 0º to the table the ball bearing didn’t move at all, that’s why I chose a position between the two. This meant it would move down fairly quickly but not too fast as that we couldn’t time it.
Here are some of our results
Tube angled at Tube angled at Tube angled at
90º 0º 35º
1st time recorded 0.35 sec's N/A* 1.96 sec's
2nd time recorded 0.39 sec's N/A* 1.92 sec's
Variable Factors
One of many variable factors would be the gradient of the tube. This must be kept at the same angle - 35º. An easy way to do this is to leave the clamp alone and only open and close the claw part of the clamp. Another factor is the temperature of the oils. To do this you must measure the oils temperature and make sure that you measure the oil, not just the water they are being heated in. The height of which the ball bearing is dropped should be kept the same so that it doesn’t gather more momentum before it hits the oil. That is why it must be dropped from the same height; I chose the rim because then I know it will always be the same. The ball bearing you use must be the same because then the resistance of the ball bearing will be the same.
Accurate Results
To ensure that I get accurate results I will try and keep the entire variable factors the same all the way through the experiment. If I do this then it will not only make sure that my results will be accurate but it will make sure that the only thing I will be experimenting is the viscosity of the oils and how temperature affects it. I will not be testing anything else.
Range of Results
I want to take 5 times from each of the oils at each temperature. If I do this then I will be able to take an average score. This is a good thing because it means that if I mess up one of the drops then it won’t matter as much because I will take an average of the 5 times.
I will set out my table like this:
E.g. Oil C6
Results
Analysis
From my table and graph I can see that