Lesson video

Hi, I'm miss Kidd-Rossiter, and I'm going to be taking today's lesson on speed as rate.

We're also going to be looking at distance time graphs.

It'd be really helpful if you had a ruler or a straight edge for this lesson, as well as your normal pen and paper.

Please make sure you're in a nice, quiet place free from distractions.

If you need to pause the video now, sort any of that out, then please do.

If not, let's get going.

So I'd like you to try this activity, what's the same about what the graph show and what's different.

If you're confident, pause the video now and have a go.

If you're not so confident, think about what are the axis showing? What are the units used? And what are the scales? There's lots of things that are the same and different.

So pause the video now and have a think out about that.

Excellent, let's go through these together then.

So one thing that's the same is that both of these graphs are comparing distance on the Y axis with time on the X axis.

So that's something that's the same, but then the units that they're using are different.

So the graph on the left is using kilometres and hours and the graph on the right is using metres and seconds.

So there's something that's different.

The scale on the X axis is the same on both, even though it's measuring something different, each one is going up in 0.

5 on both of these graphs, but the Y axis have different scale, don't they? This one's going up in tens, this one's going up in fives.

There were also lots of different things here that you could have picked up on the way either the same or different, so well done if you did.

Let's move on to the connect part now then.

So, we can describe speed as the rate of change of distance.

So speed could be described as the rate of change of distance.

So that means that we can measure speed using distance and time.

So this is really important, I'd like you to write it down.

We can think of speed as distance per unit of time.

So if we look our graph here, we can see that for one hour, so that's our unit of time, We are going 36 kilometres.

So for every, one hour, we travel or whoever this is travels 36 kilometres.

So that means that we can say that our rate is 36 kilometres per hour.

Now this is looking very similar to units that you might know for speed.

So 36 kilometres per hour.

So speed, is a distance per unit of time.

You're now going to apply your learning to the independent task.

So pause the video here, navigate to the independent tasks, and when you're ready to go through some answers, resume the video.

Good luck.

Excellent work, well done, how did you do.

Let's go through some answers here.

So if a car travels 30 kilometres per hour, then in 30 minutes, they will do half that, won't they? So 15 kilometres.

If a car is still travelling at 30 kilometres per hour, then in three hours, the car will travel 90 kilometres.

In one and a half hours, the car will travel 45 kilometres and in three hours and 45 minutes.

Now this is a bit trickier.

I would have done this one by saying, well I know, three hours is 90 kilometres, I know 30 minutes is 15 kilometres, so from that, I can get that 15 minutes would be 7.

5 kilometres, so I can add together my 90 kilometres, my 15 kilometres and my 7.

5 kilometres to get my answer of 112.

5 kilometres.

How can you describe the speed in each of these statements now? For these statements, the answers that I put on the board are one of several possible answers.

So don't be put off if you've got something different.

I'll try and talk through some of the other options, but there are multiple correct answers here.

Then Binh walks one mile in 20 minutes, so you could have left it as that.

Binh walked one mile per 20 minutes, that would have been okay, or you could have converted it to miles per hour.

So there are three 20 minutes in an hour, so that means that Binh will walk three miles per hour.

So her speed is three miles per hour.

Cala cycles 54 kilometres in three hours.

So Carla cycles at speed of 18 kilometres per hour.

Xavier swims at 150 metres in six minutes.

Well here, I did it into metres per minute.

So Xavier swims at a speed of 25 metres per minute, or you could have said that he swims at a speed of 1,500 metres per hour.

And then finally, Zaki runs 14 kilometres in two hours.

Well, that means Zaki runs at a speed of seven kilometres per hour.

Who is going faster, Antoni or Yasmin? Well, if Antoni is travelling 60 kilometres in 2.

5 hours, that means, that we can work out what one hour is by dividing by 2.

5.

So if we divide both sides by 2.

5, we get that Antoni travels 24 kilometres in one hour.

And then Yasmin, she's travelling 100 kilometres in 4.

5 hours.

So again, if we divide by 4.

5 on both sides, we can get her speed for one hour.

So that's 22.

2 recurring kilometres per hour.

So, who travels faster? Well we know that, 24 kilometres per hour must be faster than 22 kilometres per hour.

So Antoni is going faster.

The explore task now then.

The graphs below show the car, travelling at the same speed, complete the boxes in three different ways.

So you can see we've got distance travelled in miles and kilometres.

So kilometres are the one on the left and miles are the one on the right, and then we've got time in hours, at the bottom.

So pause the video now and have a go at completing this task.

If you are struggling a little bit, I've given you a couple of hints there at the bottom that might help you.

So pause now and have a go at this task.

So let's start with a simple example.

We could say that in one hour, our car travels eight kilometres.

That will mean, that this space here would have to be 16, and this space here would have to be 40.

So that's one possible way.

And similarly, if in six hours then our car would travel 30 miles, which would mean that this is 25 and this is five.

So that's one possible way of filling it out.

But there were lots of different ways that you could have done this.

So excellent job, well done.

That's the end of today's lesson on speed as rate.

So I hope you've learned a lot.

Don't forget to go and take the end of lesson quiz on this topic so that you can show me what you've learned.

Hopefully I'll see you again soon.

Bye.