Method
I will set up the experiment as shown in the diagram in order to start my investigation. But first I need to measure the length and cross sectional area of the tape accurately and attach it to the clamp stand. I can then start adding weights:-
- Measure width and depth of the cassette tape in order to find the cross-sectional area.
- Add weight holder to tape and measure the original length.
- Add a 50g weight and then measure the extension .
- Measure the reading from part 3 twice more.
- Repeat step three and four only adding an additional 50.00g each time until reaching 500.00g total.
- Gather results into a table so they can be easily compared.
- From the readings, plot a graph of force x extension.
- Find the gradient of the graph and use it to find the Young’s Modulus for the tape, by using the below formula: -
Young’s Modulus = Gradient x length
Area
There are many externalities, which could affect the results from this experiment. The length of the tape, temperature of the room, cross sectional area of tape, material that the tape is made from and even the pressure in the room, are all factors that may distort my findings. Some of these factors however will have little if not no effect on my results, so I will class them as being constant. These externalities are the pressure and the temperature in the room, due to the fact that any fluctuation in these will be very slight that it will have a diminutive effect on the results. To keep the material of the tape constant, I will use the same piece of tape throughout my experiment, also keeping it at the same length, cross-sectional area e.t.c.
In order to find a reasonably accurate result for the Young’s Modulus of the tape however, I will have to have some form of variable in order to obtain multiple results. The variable I have chosen is the weight attached to the end of the tape, which should vary the amount of extension in the cassette tape. The weights I am using are accurate to 0.01g, which I feel is a reasonable amount of accuracy for this experiment.
Preliminary Results
I decided to have a preliminary experiment as a test to see if my actual experiment is going to be accurate. Here are my results: -
From my prelims, I decided that 100.00g intervals were too large, so I will take readings every additional 50.00g in order to acquire a more reliable set of results. I could have chosen to use 20.00g intervals, but I feel this would have made the extension smaller, hence creating a larger percentage error.
When taking measurements I have to be aware of certain errors, which could affect the accuracy of my results. For example when using a micrometer you can measure to the nearest 0.01mm. This means that there is a 0.005mm chance of error. The error can be made smaller by taking a larger reading. I will do this when calculating the cross-sectional area of the tape, especially when finding the depth because this will be such a small reading and 0.005mm will make a lot of difference when calculating the area. To make the reading larger I decided to fold the tape over twenty time, which will make the depth greater, find the result and then divide the answer by twenty in order to obtain the measurement for one single piece of tape.
B.
I had to carry several, simple safety checks before starting and during the experiment. Due to the nature of this experiment there were very few dangers, but I did make sure that the clamp stand was fastened to the workbench with masking tape, so that it did not fall over when adding extra weight to the experiment. Also I made sure that the area around the experiment was clear, in order to reduce the risk of falling over, by moving such things as bags out of harms way.
There are a few areas I need to be aware of errors and in some cases take precaution with. Here is a list of the main areas in which errors can occur in my experiment: -
- Measuring the Depth of the tape.
- Measuring the width of the tape.
- The actual weight of the weights used.
- Measuring the extension of the tape.
Results
