- Clamp and stand
- Newton weights
- A weight holder
- Ruler
- Bulldog clips
- Samples of 15 and 40 denier tights
Below is a diagram of the apparatus I would use and how I would set up the experiment:
It is important that I make sure my experiment and working area is safe. To make sure my experiment is safe, I will have to:
- Wear safety goggles
- Tie hair back
- Keep feet under the table so if the weights drop, they will be protected
- Protect the floor and tables from falling weights
Prediction
I would think that the higher the denier of tights, the less stretchy it would be, and that the lower the denier the lower the tensile strength as I would assume that in the lower denier tights there would be less polymers which would mean that they cannot stretch as much and the higher denier tights would have more polymers which means they would be able to stretch more.
Recording the Results
I recorded my results whilst doing the experiment and I will put them in a table. Here are my results shown in the table. It has four columns for each type of tights, this is because I did the experiment three times for each type of tights and then worked out the average.
The calculation I used to calculate the average extension was:
(result a x result b x result c)
3
The calculation I used to calculate the reliability of my results was:
(Lowest value / Highest value) x 100
I have drawn these results on four different graphs:
Graph 1 is showing the averages for the ten denier tights plotted with error bars to show the highest and lowest values recorded.
Graph 2 is showing the averages for the fifteen denier tights plotted with error bars to show the highest and lowest values recorded.
Graph 3 is showing the averages for the forty denier tights plotted with error bars to show the highest and lowest values recorded.
Graph 4 is showing all the averages from all the tights on one graph so that I can compare the different results with each other.
The four graphs are shown below:
Graph One – 10 denier tights
Graph Two – 15 denier tights
Graph Three – 40 denier tights
Graph Four – All tights
Evaluation
I am confident with most of my results as they are quite accurate and when I calculated the reliability of them, none of the reliabilities were below 70% which means that they are quite good. Also on my graphs I have used error bars to show the highest and lowest values recorded, and there are only a few error bars that are quite big, the rest are quite small which can make me feel confident with my results. To improve this experiment, I could have used half Newton weights instead of whole Newton’s as this would have made my results clearer as to how much the tights were stretching. Also, to improve I could have repeated the experiment more times so that I would have more reliable results.
Theory
My experiment did not match my prediction as I thought that the 40 denier tights would be the stretchiest and the 10 denier tights would stretch the least but it worked out that the 40 denier tights were the least stretchy and the 15 denier tights stretched the most.
Conclusion
Conclusively my results have shown me that the tights with the biggest tensile strength were the 15 denier tights, and the tights with the smallest tensile strength were the 40 denier tights. When I put all of my graphs into one, I could see at what different points, which different tights had stretched the most.