1. 1 of 9 Data presentation Proportional circles Copyright © AQA and its licensors. All rights reserved. Disclaimer This is an example of a teaching aid to support learning in the classroom. It has been written by and is copyright of Sam Coulson, Assistant Head of Geography at William Farr C of E Comprehensive School, and is a resource she currently uses with her class. She has kindly agreed to share this resource as an example of good practice and in anticipation that other teachers will find this approach interesting and inspiring. AQA accepts no liability for the content of these materials.

2. 2 of 9 When are they used? Copyright © AQA and its licensors. All rights reserved. When you have collected data at several different specific points on a map. It’s important to recognise that this data can then be located for plotting totals of any kind. You can also work out a scale to choropleth shade your circles, which adds an extra layer of complexity. Remember to also include a title, scale and N arrow to the base map.

3. 3 of 9 How do you draw them? Step 1 – organise your data into a table – see right. Step 2 – work out the square root of each piece of data – these values are used to calculate the radius of each circle you will need to draw. Copyright © AQA and its licensors. All rights reserved. Data collection point no. Value recorded Square root value* 1400 2121 3144 4121 549 616

4. 4 of 9 How do you draw them? Copyright © AQA and its licensors. All rights reserved. Step 3 – on squared paper, draw out an axis that is large enough to include all of your square root values – see below. 01234567

5. 5 of 9 How do you draw them? Step 4 – at the highest end of the scale, draw a circle as large as you can reasonably make it. (This can be a bit of a balancing act – a larger circle will give more contrast between values, but must be able to fit well on your finished map). Step 5 – draw a diagonal line from the centre of the circle to the axis where the value is 0 – see below. Step 6 – stick both your scale and square root value table to your map (on the back if you can not fit it on the front). Copyright © AQA and its licensors. All rights reserved. 01234567

6. 6 of 9 How do you draw them? Step 7 – now use your scale to set your compasses to the correct radius (centre point to the edge) for each square root value you have – see below for the example using a square root value of 4. Step 8 – draw the circle on to your map, so that the data collection point is located at the centre of your circle. Repeat this for each data collection point. Copyright © AQA and its licensors. All rights reserved. 01234567

7. 7 of 9 What do you get marks for? In your ‘How to…’ booklet, there is a checklist for each section to work alongside the mark scheme. You must fulfil all of one level to progress into the next one. Using the things that you have just learnt and the how to booklet, write a checklist of things that you must do when creating your proportional circles. Copyright © AQA and its licensors. All rights reserved.

8. 8 of 9 Adding a choropleth scale To make you proportional circles even more complex and open up opportunities for higher marks you can add a choropleth scale. Step 1 – using the raw data (average noise level) separate your data into three groups, these do not need to be even, but must incorporate all values from 0 to above your highest value. Copyright © AQA and its licensors. All rights reserved.

9. 9 of 9 Adding a choropleth scale Step 2 – draw out and label a scale on your map, add three boxes and write the corresponding values next to them – see below for example. Average noise levels (Db)  0 – 5.9  6 – 19.9  20 + Step 3 – pick a colour and shade each box in your scale, using the lightest shade for the lowest values and gradually getting darker to represent the highest values. Step 4 – now shade your proportional circles to correspond to your choropleth scale. Copyright © AQA and its licensors. All rights reserved.