This is a helpful guide on practical skills for your physics ISAs.
I advise you read through the OCR Practical Skills Handbook. It is from that support material and own knowledge that information has come from.
1 - Measurement and observation
The minimum number of observations to be made is 6. This is for a linear line to be clear and 9 is the expected number of readings for a curve to be clear. You will not be penalised if you use 6 readings, so use this number unless you feel you should do more. Never do less than 6 readings. Use normal intervals between the readings, such as 5(units) or 10(units). Do not use something like 7(units).
Now, also in the task it will provide you with a range of data to be taking values from and ensure you make the readings within this range.
2 - Repeated readings
You're expected to make repeated readings and then take the average from these readings. Take three to ensure you get a good average that you can see any outliers on. With two results that are…