GCSE Mock revision 2023

What is uncertainty?

Your mock revision sheet mentions uncertainty, but what is this? AQA defines it as:

"The interval within which the true value can be expected to lie. Whenever a measurement is made, there will always be some uncertainty or doubt about the result obtained. Uncertainty can be expressed in terms of spread of values obtained. For example, a length of 56 cm ±2 cm would mean the true value could be anywhere between 54 cm and 58 cm."

You can find a link to more terminology here

How do you calculate uncertainty?

You may be presented with a range of data in the exam and be asked to calculate the uncertainty.

For example:

Four different people timed an athlete running a 100m race and they recoreded the following times:

11.2s, 10.9s, 11.1s, 11.3s

Find the mean time and the uncertainty.

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The average time is 11.1s

The uncertainty can be found by taking the maximum and minimum time and diving by 2.

(11.3-10.9) / 2 = 0.2s

The final answer can be written as the mean time plus or minus the uncertainty: 11.1 ± 0.2 s

We now know that you will be given all of the formulas for you exam in the summer. Therefore we will also give you a full formula sheet for your mock.

Although we do not have a copy of the formula sheet you will be given yet, we assume that it will be the same as the 2022 formula sheet which also had all of the equations. A copy of this formula sheet is shown below and it has been manually coloured in so you can see where the equations for each topic are.

Look for AQA GCSE physics

https://isaacphysics.org/pages/exams_2022?stage=all#aqa-gcse-phys