Lesson video

Hi there, my name is Chloe and I'm a geography field studies tutor.

This lesson is called "Fieldwork: Presenting Soil Data" and it forms part of the Rocks, Weathering, and Soil: Why Is Geology Important unit of work.

We're going to be looking at soil texture data and how we might be able to present it in more interesting and creative ways, perhaps in ways that you've never heard of before as well.

Let's get started.

By the end of this lesson you will be able to present soil texture data using creative techniques.

Let's take a look at the keywords we need to think about during this lesson.

First of all, proportional data.

This is data that can be split up into constituent parts.

A triangular graph is a graph with three axes and it's used to display proportional data with three constituent parts.

A proportional shape is a symbol on a map or on a graph, and that shows the value of data by the size at which it has been drawn.

There are two parts in this lesson.

We're first going to be looking at how we might present proportional data, and then we're going to be a bit more creative and a bit more experimental and look at some different ways of presenting our data as well.

Let's start by looking at what proportional data is and how we might present it.

So you can see, we've now moved on to the third part of our inquiry cycle.

We are looking today at the data presentation.

So here's our raw data from the field and you can see there are different types of data that have been collected during our soil texture survey.

The one we're interested in right now is this one at the end, the soil type, because this is proportional data.

It is made up of three parts: sand, silt, and clay, and we've presented it here as percentages.

Proportional data is often shown in a pie chart.

You can see an example of one right here from our data.

It's site two, our flower bed data.

Laura says, "From the pie chart I can estimate that 55% of the soil is sand, 35% is clay, and 10% is silt." She's using the key and she's estimating roughly what proportion of the soil falls into each of those three categories.

Pie charts are drawn so that the largest percentage starts at the 12 o'clock mark and each segment gets progressively smaller from there in a clockwise direction.

You can see in our example that sand has the highest percentage of our three constituent parts.

So it's the one that starts at 12 o'clock.

Clay is the next largest, so that comes next and silt is the smallest.

So that finishes off the circle To know the size of the different pie chart segments in degrees, we calculate the segment value divided by the total value times 360, because there's 360 degrees in a circle.

You can then use a protractor to draw each segment.

So in our example, sand made up 55% of the soil sample at site two.

So we do 55 divided by 100, that's our percentage, times the 360, and that's the degrees of the circle, and that comes out to 198 degrees.

So I use my protractor to draw my segment to 190 degrees from that 12 o'clock position.

Proportional data does not have to be drawn using a pie chart, though it is the most common way it is shown.

A percentage bar divides a bar into proportional segments.

So here we've taken the idea of pie chart, but we've turned it into an oblong.

It's a bar instead.

And you can see it runs from zero to 100 and we've divided up the bar into the right amount for each of our soil types.

You can also use something called a waffle chart.

You might be able to guess why it's called that.

This is a 10 by 10 grid with each square in the grid representing 1%.

So we simply shade the number of squares that represent a certain percentage.

So if we've got 55% sand, we will be shading 55% of the squares or 55 of the 100 squares in the colour for sand, which in this case is the purple colour.

So let's check our understanding of that so far.

Pie charts are not the only way to present proportional data.

Is that true or false? Pause the video, have a think, and then come back to me.

Well done if you remembered that it is true.

Now, tell me why it is true.

Yes, you're right.

Proportional data can also be presented using percentage bars and waffle charts.

Soils have three constituent parts as we've already seen, sand, silt, and clay.

This means geographers often use a triangular graph to show this data.

The data is read off three different axis lines.

We've got the X-axis, in this case that's going to be the silt; the Y-axis, in this case that's the sand; and the Z-axis, and that's the clay.

Soils are plotted onto the graph according to their structure.

So if we look at the pink dot here as representing a site within our school grounds, this soil is 55% sand, you can see that's read off the Y-axis, 35% clay, you can see that that has been read off the Z-axis, and 10% silt, and that's been read off the X-axis.

Different sites can be plotted on the same graph and this helps geographers to actually compare the sites.

Here, you can see we've got four pink dots representing the four sites in our own investigation.

Maybe it's not surprising that those four sites are actually fairly close to each other on the triangular graph.

In the grand scheme of the UK, the four sites are really, really close together so perhaps it's not surprising that the four soil types are actually fairly similar.

If we were comparing soil samples from Northern Ireland, Wales, Scotland, and then England, we might expect to see them occupy very different parts of the triangular graph.

So now, a check for our understanding to do with triangular graphs.

Which line in the table represents site number one? You can see the figures that are associated there and the sand, silt, and clay percentages.

Pause the video so you can read to the triangular graph carefully and see which of those options best fits site number one.

Well done if you recognise that it is option C.

Let's just check it on the graph together as well.

So we're expecting our sand to be 10%.

You can see that's where it falls on that Y-axis.

Our silt should come in at 50%.

Yep, there it is on the X-axis.

And our clay is at 40% and there it is on the Z-axis.

Well done if you got that.

Here's our first practise task of this lesson.

Produce a triangular graph of the soil type data you collected around your school site.

Make sure your data presentation includes all the elements that make the graph both readable and correct.

You will definitely want to pause the video here and do take your time creating those plots on the triangular graph.

It is not always easy to get it right the first time 'cause you've got a lot of numbers and they seem to be in running in different directions.

So do take your time and make sure that you're using those axes correctly to plot your sites.

Here's an example of the kind of thing that you might have produced.

You will have your four plots onto your graph and it's a good idea to actually have them in a recognisable colour so they really stand out from the graph.

So your graph might look a little bit like this.

But as well as doing the plots, we've also gotta make sure that our graph is readable and correct.

Here's what your answer should include.

You need to have a title.

In this example, I've chosen this one, "A triangular graph to show soil types at the four data collection sites in the school grounds." Your axes need to be labelled.

Sand, silt, and clay need to be in the right positions on each side of the triangular graph.

You also need to make sure you've got units on each axis.

So you've both got the numbers from zero to 100 plotted, but also that you've got that percentage next to your label on the axes.

And you need to make sure your sites themselves, for your pink dots, need to be numbered or named so that it's really clear which one corresponds to which site in the school grounds.

Well done if you've got all of those ideas on your graph.

We'll now move on to the second part of the lesson where we're gonna be looking at how we can be a bit more creative and a bit more experimental with our data presentation techniques.

To see if there's a relationship between soil type and infiltration rate, Alex needs to present these two data sets together somehow.

Let's listen in on his conversation with Sam to see what he's thinking.

He says, "If I use a waffle chart, I could add a graphic over the top to show the number of seconds it took for the water to infiltrate." So he's got his soil type in the waffle chart, but he wants to include as well the data to do with infiltration.

So he's suggesting a graphic could sit on top of the waffle chart.

Sam says, "Well, you could place a stopwatch over it with a reading of the number of seconds that it took." And here's an example of what Sam's thinking of.

Now from the look of things, Alex is not sure if this is a good idea.

He says, "I'm not sure this works." And Sam replies, "Yes, you can't actually read the soil types now.

Let's make the stopwatch smaller." There we go.

Alex says, "But now it's too small and I can't read it." What else could Alex and Sam do to present this data? They've got some good ideas, but they're experimenting to see what works.

What else could they do? Well, Lucas has joined the conversation now and he says, "A full clock face is one minute.

We could create a stopwatch symbol to show the amount of time with a coloured segment and place it next to the waffle chart." So now it's not over the top of the chart, we can read the waffle chart.

And the stopwatch is to the side, and instead of numbers we've actually got a coloured segment.

That's really clever.

Alex says, "And I could draw it so it looks like the water is passing through the soil." So now we've almost got a picture that looks like the actual situation.

We've got the different soil types sitting underneath the ground level, there's water passing through the soil, and there's a stopwatch showing how long it takes.

They've actually come up with a really clever way of showing this data now.

Alex, Sam, and Lucas have come up with a creative solution to their data presentation.

They experimented with different ideas before they decided on one that worked.

They have combined techniques together to allow them to see any relationships between the data.

Let's check our understanding so far on that.

Complete the sentences with the missing words.

Do pause the video here so you can scan through the paragraph below.

And then you actually have a think about what words are gonna be best fitted into those gaps.

Also, have a chat with someone nearby to see if they agree with you.

Pause the video and come back to me with some good answers.

Let's see what answers you got.

Geographers often have to try to come up with creative solutions to their data presentation.

They often experiment with different data presentation techniques before they find one that works.

Data on soil compaction also needs to be added to the data presentation for each of the four sites.

So Lucas is having a think about this now.

"We have shown infiltration happening through the soil.

Maybe we should show compaction happening on top of the soil." It makes sense.

You're gonna continue this idea of the data presentation being almost like a picture of what is happening in the data.

Sam says, "We could use a hammer symbol to show compaction." It looks a little bit different from maybe the one that used in the field, but it's definitely identifiable as a hammer.

Sam says, "The size of the hammer could represent the number of times we had to strike the auger." So the smallest hammer means that one strike happened on top of the auger, and the largest hammer represents four strikes.

This is known as a proportional shape.

The larger the shape, the larger the value it represents.

One may not need to read the key in order to understand the general trend in the data.

If we combine all the ideas together, we have a creative piece of data presentation.

So here we have the real data for site two.

You can see we've got a small hammer representing a small amount of strikes on the auger, and that means that the soil is actually not compact at all.

It's very low in value in terms of its compaction.

Our soil type is represented by our waffle chart and our infiltration rate is represented by our segment on our stopwatch.

Let's check our understanding of that.

What is one benefit of using proportional shapes for data presentation? A, one may not need to read the key to understand the nature of the data.

B, the shapes look like the actual size of something.

C, the different sizes make the data presentation attractive, or D, the shapes show the exact values of something.

Which one of those is the benefit of using proportional shapes? Pause the video, have a think, and then hopefully you'll come back to me with the right answer.

So, what did you get? Hopefully it was answer A.

Yes, you don't need to necessarily be able to read the key in order to understand the nature of the data.

With a proportional shape you will always know that the largest value is represented by the largest shape as it is drawn.

Now our second practise task of this lesson.

Design a creative way of presenting data for your data collection sites.

You may wish to collaborate with others to try out different ideas.

See what works and what doesn't, critique each other's work, and hopefully you'll be able to come up with something which is both creative and that works well as a piece of data presentation.

Present your data then using your chosen data presentation techniques.

Write one reason why you have chosen to present your data in this way.

This is gonna take a little while, so do pause the video.

Have a really in-depth discussions with people around you to see what they think works well as a piece of data presentation and what might not.

All of those discussions will inform you to create a really good piece of data presentation.

Pause the video and I'll show you some of my ideas in a moment.

Well of course, I've now presented this data for all of my four sites and when they're sat side by side, you can actually really start to see the difference in the sites and how the compaction rate and the infiltration rate differed between them.

Your presentation will obviously look different to mine, but I hope you've managed to come up with something really creative and really interesting for people to look at.

Do make sure that you've got a key that is included with your data presentation so that it is readable and it actually has meaning.

Then I asked you to think about a reason why you've chosen to present your data in this way.

So your answer might include something like this.

The waffle chart was a quick and easy way to see the proportion of different types of soil at each site.

Combining the three elements of the data together in one data presentation method means we can see how the elements relate to each other.

Let's now summarise our learning for today.

Geographers may use a variety of different methods to present proportional data, including triangular graphs.

Sometimes geographers have to experiment with different styles of data presentation to see what works for their circumstances.

And proportional shapes are used to show the value of data according to the size of the shape.

Well done.

I hope you enjoyed that lesson because it gave you the chance to be a little bit more creative.

Sometimes geography field work can feel very scientific, particularly in the way that we go through the inquiry processes.

But in the data presentation, providing you are allowing the data to show its true meaning, there is an opportunity to perhaps bring in a little bit of creativity.