Reading and interpreting bar graphs

Key Stage 2

Maths

Graphs

If this symbol represents 3, how many would I need to use to show 15?

In this graph, how many people travelled by train?

Using the graph above. If 2 more circles were added to the walking column, how many would have walked in total?

Looking at this graph. How many more circles will I add to the bike column if 6 more people say they travelled that way?

﻿Hello there, everyone. I'm Miss Brinkworth. I'm going to be doing this lesson today with you all about bar charts. Let's get going. Right, so we're reading and interpreting bar charts today. That's just a way of saying that we're going to make sure that we can understand really clearly what they are trying to tell us. So remember that we're talking all about data. So this is just a different way, another way of representing different data. So if we look at today's lesson agenda, we are going to see just recapping a little bit all about data and pictograms to get us started. We're then going to explore different bar charts and what they're telling us. It'll be then some opportunity for us to answer questions looking at bar charts. We'll do some of those, we, as in all together, and then you will have a chance to do that independently, as well. And then the end of the lesson is that quiz where you can see how well you've taken on today's learning. Okay, so all you'll need is pen or pencil, paper, and a great attitude. So here's a little warmup for you. Nothing too much to worry about. Just some times tables. So pause the video here and have a go at those. How did you get on? Let's just go through the answers and then I'll explain to you why it's important to know these times tables for these lessons. So two times four is eight. The next one where we've got the number missing at the beginning, you could see it as a times table or as a division. So it could be do you know which in your four times table equals 12, or you could look at 12 divided by four. Either way you'll get the answer three. Four times by, ah sorry, 10 times by four, many people like their 10 times table as it has that really nice pattern to it, so 10 times four is 40. Two times three, hopefully you're all quite good with your two times tables by this stage, is six. Five times by five is 25. Again, people normally quite good at those ones where it's five times five or four times four where it's a number times itself. Those ones seem to stick quite well. Back to our 10 times table here then, what is it that I times 10 by if I've ended up with 70? It's seven. Something times by two is 12. That one's six. Something, no, sorry, eight times by two is 16. And finally, in our five times table we have times five by 10 to get to 50. Now the reason our times tables are really important when we're looking at data and graphs is because we have that scale. So in pictograms it could be that each picture represents two, or three, or five, and so we need to know that times table so we can look at those pictures and clearly understand what it's telling us. With bar charts today we have a scale, so let's move on and start looking at what we're talking about. Recap quickly then on pictograms. So pause the video here and just have a go at answering these questions true or false looking at this pictogram. Now this is a really useful way to start our lesson because pictograms and bar charts have got lots in common. If we can just recap what pictograms tell us, how they work, it's going to really help us apply that knowledge to our bar charts for today's lesson. So is it true or false that in this pictogram five people have a dog? Well it is both. I wonder if you can see why people might think that's true. Some people might look at the smiley faces on that pictogram next to the dog and say, "One, two, three, four, five; yup, dog is five." But they won't have read one important part of the pictogram, and that's the scale. Well the scale is telling us that actually each smiley face represents two, so it's 10 people that have a dog. So well done if you could see that that statement was in fact false. What about three people have a tortoise? That one is true. You've got that half smiley face there to show you that you've got two and one, so you've got three for tortoise. Well done. More people have a cat than a dog? Well we don't even need to count them up to see that the dog row has got more in it. It goes on further than the cat row. So we can see that that statement is false. So what about double the amount of people have a dog than have a rabbit? What do you think? Well I think looking at it the dog row is very long and the rabbit row is really quite short. I don't think it's just double. So that one's false, as well. And if we just go back to that question and just look at it in a little more depth, rabbit is four, isn't it? Two and two, two and two, four for rabbit as we've got those two smiley faces. Whereas dog we've got two, four, six, eight, 10. So it's not double; it's more than that, actually. Okay, so here's our new learning then, bar charts. Here's what they look like. They aren't that dissimilar to pictograms. They can come in columns like this one or they can be in rows. There's some other similarities as well, aren't there? Have a good look at that bar chart. What similarities can you see? So this one is showing the weather over a month, and that is its title. You will have looked at titles before with pictograms, so it has a title that tells us really clearly what the chart, the graph is all about, and this one is about the weather over a month. What else has it got then that's really quite similar to a pictogram? Well it's got these axes, and it's got two this time, a y and an x. So one of them will always have the type of thing that we're describing, so that might be the type of pet someone has, or the weather, or where people live, or what their favourite colour is. Here we've got that going along the bottom on the x-axis. The other axis on a bar chart always has numbers on it. There'll always be a scale, and that's how it's different from a pictogram. Let's just have a good look at that bar chart for a moment. Okay, let's have a peek then. What does this bar chart tell us? What can we tell from this bar chart? So we need to read it really carefully. Look at the axes really carefully. We know that it's all about weather, but which column is the largest? Which column is the smallest? Can you see? Hopefully you can see that the sunny column is the largest. That's that one on the left there that goes all the way to the top of the scale. The sunny column is the largest. And the smallest column, well rainy is really quite small. So without looking at the scale in too much detail you should be able to see from this bar chart that there were far more sunny days than there were rainy days. So that's just some general things that you can see when you're looking at bar charts. But you could also go into far more detail and be far more specific. So you can answer questions like this one: How many windy days were there? How many windy days? Well if I look at the scale on that y-axis, the y-axis is the one that goes vertically, that's where I'm looking at that scale, can you see which times table that's going up in? Can you see? It's actually just going in one. So it's nice and easy for us to read. It goes one, two, three, four, five. And if I look at windy, it's gone up those four steps, and on the scale that means four. So there were four windy days. How about cloudy days then? How many cloudy days? Can you see? Well, again, I can look across, I can sort of draw an imaginary line across to the scale on the y-axis and it says nine cloudy days. But I think you might get a question like this last time: How many more windy days than rainy days? Now a how-many-more-question is almost always take away. So we could take away the windy days, sorry, the rainy days from the windy days. But actually, I can see that windy is four and rainy is just two. Four take away two is two, so the answer to that question is two. Moving on then, have a look at this bar chart. Have a think about what is the same, what is different to the one we just looked at. So we can see that we've got those columns again. But actually, the y-axis is a bit different this time. We've got a scale that's not moving in ones any more. Can you see the times table that's being used on that y-axis? Hopefully you can see two, four, six, eight, 10, we've got our two times table there. So these ones are jumping up in twos each time. So here's our axis and our title. And hopefully likely you can see that that y-axis is using our two times table this time. Okay, so pause the video here and have a go at answering these questions. Okay, how did you get on? You can see that the questions are really similar to ones that you might have looked at for pictograms in the past, and it's really important to read that scale carefully as you go through. So which transport is eight? How did you get on with that one? Well if I look at eight just below 10, it's not walk, that one goes all the way up to 10; it's not bicycle, that's only six; car is smaller so I don't need to look at that one; and the answer is, well done if you got that. Which is the most common? So the one that comes up the most often, the one that was used the most by people, that's going to be the one with the tallest column. And hopefully you can see that that's walking. Is there a transport which has no one? And we can see that there is a transport there which has no column, so zero people must have picked it, and that is motorbike. And then finally, which one is double the car? Well the car there has got four, so I'm looking for one which is eight, double the size of that column, and that one was bus. Really well done if you got those answers right. Don't worry if you're making a few mistakes. You're brand new to bar charts. You're doing really well. Okay, here then, if we have to adapt the bar chart. What if actually we've missed some information? Now we've made a mistake. Actually, we did pick people who went by motorbike. It was nine people. How would I add nine people onto this bar chart, especially as I don't have nine on my y-axis? What can I do? Well, I'd have to go halfway between eight and 10 because nine comes halfway between eight and 10. So I'd have to think about that line really carefully coming halfway between eight and 10 where nine sits and then I draw my column really carefully, really scientifically, really mathematically, perfectly halfway between eight and 10 so it's really clear to the people reading my graph that the number I'm trying to tell them is nine. Okay, there's some other questions for you to have a go at here on a completely different kind of bar chart. And this time you can see that we've actually got rows this time instead of columns. You read it in exactly the same way. It's just that your scale is along that x-axis on the bottom now. So have a look firstly at what scale is it, what times table is it using, and then just have a go at those questions which are true or false. How did you get on? Let's have a look at them together then. True or false, one yellow car went past? Do you think it's just one? Well, if I look at that tiny little yellow column, it's not got all the way to the two line. The two's got that nice line on it to help me. It's only halfway. Halfway between zero and two must be one. So that statement is true. What about blue is the most common colour? Blue is the most common colour. Well, actually, I can see that it's black which has got that longest row. I can see that it's much longer than blue, so that statement is false. And well done if you could see that. Four and a half white cars seen? Hmm. That doesn't quite sound right, does it? We can't really see half a car. Why might someone think that it was four and a half? Well, I think that's because it comes halfway between four and six. But halfway between four and six isn't four and a half. Four, five, six, so that statement is false. There were five white cars. And the largest number in one colour is 13? Well we've seen that black is the most common, so we just need to see what that black row is showing us. And yup, we can see that it's halfway between 12 and 14. And halfway between 12 and 14 is 13. So that statement is true. Really, really well done. Okay, in other questions you might need to compare bar graphs. You might have two. And these ones, as you can see, show how people travel to school in the morning and then how people travel to school in the afternoon. So we can have two bar charts and we can compare that data. We might want to know: Do more people get the bus in the morning or in the afternoon? Do more people walk in the morning or in the afternoon? So it's really good sometimes to have these two bar charts next to each other. So what can you see comparing these two bar charts? Well if we do look at walking, in the morning I can see that that's 10, whereas in the afternoon, I can see that's only six. So I can say less people walk in the afternoon than they do in the morning. I can see that from this data here. Do you notice any other differences between morning and afternoon? Well let's have a look together. What about here with trains? In the morning, two people took the train. Can you see how many people took the train in the afternoon? It is zero. That train has got no column next to it, so zero people took the train in the afternoon. So we can see these trends, we can see these patterns, and we can make statements about how this bar chart compares with that bar chart. Okay, time then for you to have a go at the independent task. Pause the video here for as long as you need to. Come back together and we'll have a go at the answers all together. How did you get on? Let's have a look. Don't worry too much if you're getting some questions wrong, but do look at the correct answer and have a think about what's maybe the mistake that you made. Okay, we've got some nice questions here on this chart, this bar chart. And you're being told to look carefully at the x-axis, and that's because that's where your scale is. And on this x-axis, it's going five, 10, 15, 20. What times table is that? It's our five times table. So make sure when you're reading this that you've thought carefully about your five times table. How many people came by train? Well, that's a nice one 'cause it's right by the x-axis. So it really clearly comes up to 10. Well done if you could see that. Which was the least popular? So which transport was used by the fewest number of people? Which row is the smallest? Well done if you could see that that was the motorbike. Which transport was twice as popular as motorbike, the row which is twice as big as motorbike? Well, motorbike uses up just one square, and that's five people. So I'm looking for one which uses up two squares and is against 10. Well we've seen that it was train that was 10. Well done if you got that one right. You really understand how to read a bar chart and you understand that word double, so really good. Which transport was used by 20 people? Which one matches up with 20? Well done if you could see that was bus. Really good work. Let's just move on to Part B then. So true or false then. Oh, this should say Part B. It says Part A. Nevermind. Is it true or false that it rained for 15 days in January? Well, if I look at the January column, I can see that it matches up perfectly with that line that goes across to the y-axis and says 15, so that one is true. The only month it rained 20 days was April. Well let me have a look. April matches up to the 20 line. Is it only one which matches up to the 20 line? Yes, it is. Is it true or false that it rained exactly 25 days in just two months? So I need to look at that 25 line. Is it just two days which match up perfectly to that 25 line? No, there are three days, there are three months, sorry. October, November, and May are all perfectly on that 25 line, so exactly 25. Well done if you could see that one before. The month it rained the least was January. That would mean it would have the smallest column. Has January got the smallest column? That one is false. Well done if you managed to get all of those questions right, or even just some of them, as this is brand new learning for you. Really, really good work. Okay, share your work, if you would like to. Please speak to a parent or carer who can share your work on Twitter tagging @OakNational and #LearnwithOak. And before you go, please do that exit knowledge quiz just to see how much of that learning's gone in. Really well done today, guys.

Reading and interpreting bar graphs

Reading and interpreting bar graphs

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UnitMaths / Graphs

Maths