• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9
  10. 10
    10
  11. 11
    11
  12. 12
    12

Investigation into the effect of temperature on viscosity

Extracts from this document...

Introduction

Investigation into the effect of temperature on viscosity

Introduction:

The task is to investigate into the effect of temperature on viscosity based on two main variables, the temperature of the honey (the fluid used) and the time it takes for a ball bearing to travel through a distance at its terminal velocity. Using Stoke’s law and knowledge of the flow of fluids investigate how the fluid temperature and the terminal velocities of a ball bearing are related to viscosity.

Basic setup:

image00.png

First thoughts:

The above rough experimental design has much room for improvement. A greater level of accuracy can be achieved by using a combination of more sensitive equipment and a better overall setup. A formula linking viscosity and time will be derived and a graph of viscosity against temperature will be produced.

Derivation:

Diagram of variables and constants:

image01.png

F= viscous drag force, N/force, N

r= radius, m

η= co-efficient of viscosity, Nsm-2

v= velocity, ms-1

W= weight, kg

g= gravitational field strength, 9.81ms-2

a= acceleration, ms-2

ρ= density, kg m-3

s= displacement, m

t = time, s

A formula linking η (viscosity) and t (time) must be produced.

The following consists of rules and principals that could be applied to this situation.

Archimedes’ Principle: When a body is partially or totally immersed in a fluid the upthrust is equal to the weight of fluid displaced.

Viscosity can be defined as a measure of resistance to flow that a fluid offers when subjected to shear stress. The viscosity is due to the friction between layers of the fluid.

If an object is dropped into a fluid it experiences two primary forces, weight, which acts in the downward direction and also upthrust (equal to the weight of fluid displaced). If these values are equal then there will be no resultant force.

...read more.

Middle

Cooling the honey

Ice is added to the water surrounding the measuring cylinder to cool the honey, again the honey is stirred to produce a constant temperature throughout the honey.

Apparatus:

- Ball bearings

- Bunsen Burner

- Measuring cylinder

- Large beaker

- Ruler

- Wire gauze and tripod

- Timer

- Magnet

- Honey

- Safety goggles

- Thermometers

- Stirring rod

- Marker pen

Plan:

  1. Before beginning the experiment all equipment will be checked, i.e. functionality of the stopwatch and heating equipment.
  2. Next the apparatus will be setup as in diagram 3.
  3. Stability of the apparatus will now be checked.
  4. The markings will be added using a pen and ruler, the distance markings are made with a gap of 11cm. The volume marking will be made at the 100cm³ mark. This level of honey allows the ball enough time to reach terminal velocity (as found in the preliminary investigation) and also allows the ball to start at its rest position. If the ball was dropped through the air and into the honey it could accelerate past its terminal velocity (in honey), meaning it would be travelling faster than it should as it moved through the honey. Therefore the ball is dropped from the surface of the honey with its initial velocity equalling 0ms-1
  5. A micrometer screw gauge will be used to accurately measure the diameter of the ball bearing in use.
  6. The stop watch will be setup and readied while the correct temperature is being met. The hot temperatures will be met by heating the honey to the desired temperature (through the transfer of heat energy from the hot water). The colder temperatures are met in a similar way, by reducing the temperature of the water. Once the thermometer has reached the desired temperature the experiment may begin.
...read more.

Conclusion

Ball bearings with different radii could be used. This would allow a greater spread of results giving a better average selection of viscosities.

The main problem with the investigation was human error with the timing. This problem can be completely eliminated with the use of light gates. The light gates would have to be able to measure across a large distance due to the specific path the ball bearing takes through the honey. But once setup correctly they could time with far more precision.

The other problem with the investigation is the temperature. The way this could be solved is by heating the whole room to the desired temperature. This would require large industrial machinery, but would allow the honey to be accurately heated/cooled to the desired temperature, maintaining equilibrium of temperature throughout the honey. A more likely solution would be the use of a water bath, although this would not be as effective.

A more suitable release mechanism could be implemented so that the ball is dropped directly onto the honeys surface and is dropped centrally as well. This would help prevent the problems caused when the ball moves at angles and is affected by the extra friction imposed on it by the walls of the cylinder.

A complete change of the basic experimental setup could be used. A viscous drag viscometer could be used to measure the viscosity. The apparatus could be enclosed in the same temperature controlled room, this would allow the viscosities to be accurately measured and the results from the two investigations could be compared. One problem that may occur with this is that a metal is used to control the needle for the display. A suitable metal that is not affected by heat (through expansion) would have to be used.

...read more.

This student written piece of work is one of many that can be found in our GCSE Forces and Motion section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Forces and Motion essays

  1. Investigation into Friction.

    Accuracy We need to work out the maximum percentage uncertainty for the graphs of the results that we have produced. To do this, we can use the distance any point is from the line of best fit, and divide it by the point where it should be, on the line of best fit.

  2. The effect of the temperature on the viscosity of the syrup.

    it's weight W, acting downwards II. the upthrust U due to the weight of fluid displaced, acting upwards III. the viscous drag F, acting upwards The resultant downward force is (W - U - F) and causes the sphere to accelerate until its velocity is zero, and so the viscous

  1. Viscosity - Comparing the viscosities of different liquids.

    * I will use safety glasses in case the cylinders break out Apparatus required to carry out the experiment: 1. Ruler 2. Clamp 3. Clamp stand 4. Safety glasses 5. G Clamp 6. 3 Cylinders 7. Magnet 8. Ball bearings 9.

  2. Bouncing Ball Experiment

    It will be vinyl tiling. The same square of tiling will be used throughout the experiment so that inconsistencies between different floor tiles do not affect results. Safety: * The clamp stand will be clamped down to the desk using a g-clamp to prevent it falling over and causing possible injuries.

  1. An Investigation into the terminal velocity of steel ball bearings in Glycerol.

    The density of the glycerol and ball bearings were determined. Weighing an empty glass beaker, and then measuring it again with 100ml of glycerol measured the density of the glycerol. Problems The tube in this experiment is very narrow, and so there was probably extra friction created from the sides of the tube.

  2. What is the effect of mass on friction?

    8.1 8.8 8.4 From these results, it was possible to plot a graph for each table, plotting Pav on the y axis and Weight on the x axis.

  1. Practical investigation into Viscosity in liquids (Stokes Law).

    Angle of descent Finally the fourth experiment compared angles of which the ball bearing descended through a liquid. The results showed a greater angle to the vertical reduced the speed of decent through the liquid. Initial apparatus The following apparatus was used to complete the investigation: 2.2 metre plastic tube (colourless)

  2. Practical Investigation Into Viscosity

    Another surprise is that pressure has very little effect on viscosity. Viscosity's virtual independence from pressure means that water flowing in a pipe has an insignificant change in friction whether at 60 psi or 20,000 psi! This independence even applies to gases.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work