Are you Certain?
Your upcoming task, the Extended Practical Investigation (EPI) is coming up. This is going to be hard – you have to plan, conduct and report upon a specified task without support from your teacher. I will be present in the classroom, but will be assessing your laboratory practice and questioning your decisions.
You all know that the task is to determine what metal the wire you are given is made of by determining it’s resistivity. You *must* research resistivity – the minimum you must know is how to calculate it, how to measure it and how to interpret it.
Measurement is an issue in all experiments, but the EPI requires that you know how to measure, and how to evaluate the accuracy of your measurements.
Here are the links you need:
Measurement Good Practice Guide
Here is the Task Guidance Document (2011 EPI report guidance) and the Assessment Rubric Document (2011 EPI Criteria).
The task will be to determine the composition of an unknown wire by calculating it’s resistivity. You must develop your own technique for doing this. As a STARTING POINT, you may look at the following video and read this sample practical.
To those of you not picking up hints today, the information provided in the sample practical and the below video are NOT SUFFICIENT. You must demonstrate independent capability to develop a experimental process. Duplicating what others do in the classroom is also INSUFFICIENT. Ensure that you are ready; have a process that you have developed and that you can JUSTIFY.
See you in Class!
ps. This task is amongst the hardest things you will do this year. Some amount of panic is appropriate!

May 16, 2011 at 8:38 PM
hi sir…
A very usefull information thankss
May 18, 2011 at 8:31 PM
Thanks for the video sir, but the formula they use for resistivity is different from what i have learned being resistivity= ra/l?
May 19, 2011 at 8:02 PM
That formula is correct; what are you using?
December 11, 2011 at 10:29 PM
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