Lesson video

Hello, everybody.

It's Mrs. Franzsen here.

Welcome to Computing.

It's really great to have you in this lesson today.

We are going to be learning all about moving sprites.

Our objective today is, "I can explain how a sprite moves in a programming project." Let's look at the keywords for today's lesson.

The first keyword is sprite.

Sprite is a graphic object that can be controlled by a programme, and this little ladybug here is an example of a sprite.

The next keyword is event.

An event is an input that triggers a block of commands to be run.

In the first part of the lesson, we are going to look at investigating sprite movement.

Scratch is a block-based programme that can be used to create projects.

A sprite is a graphic object in Scratch that can be controlled.

Let's look at some examples of sprites.

I've got three sprites here on my slide.

Scratch has got lots of sprites, which you can choose from or you can even draw your own.

Blocks need to be added to a sprite to control it.

Here are the blocks that can be used, and here is the code area where blocks are placed to control sprites.

Over there is the stage where sprites will perform the actions of the blocks.

Think of a digital game that you have played recently.

How do you control movement in the game? Maybe the game was a mobile game on a phone or a tablet.

Maybe you used a controller to play the game.

Maybe you used a keyboard to play the game or a mouse.

Think about your answer to this question.

What controls can be used to move a sprite in Scratch? In Scratch, a keyboard and mouse can be used to move sprites.

Sprites will not move on their own just by pressing the keyboard or clicking the mouse.

Sprites need code to react to.

Event blocks can be used to start the sequence of commands.

We've got three event blocks here.

We've got when the green flag is clicked, we've got when the sprite is clicked, and we've got, when space key is pressed, an event is an input which triggers a block of commands to be run.

This event block will run a set of commands when the space key is pressed.

You can see there in the Dropdown menu that space has been selected.

This can be changed to any key on the keyboard.

This event block will run a set of commands when the sprite is clicked.

This is one way that the mouse can control sprite movement.

Let's do a check here.

What kind of block is this? This is, hmm, block.

Is this block, A, a motion block, B, an event block, or C, a start block.

Pause the video here to think about your answer.

Welcome back, well done for thinking about that question.

This block is what kind of block? The answer is, B, an event block.

Well done if you got that right.

The glide motion block can be changed to the mouse pointer option.

This lets a sprite follow the mouse pointer.

Let's do a check here.

True or false, sprites will move when you press a key or click the mouse even if they don't have any code.

Pause the video here to think about your answer.

The answer was false.

Why? Sprites always need code to control their movement.

Well done if you got that one right.

The creator of this programme did not write any instructions.

You can see that the box marked "Instructions," is empty.

You'll need to try out different ways of controlling the sprite to see what the actions are.

Use the green flag to reset the sprite.

This means the sprite will go back to its starting place.

All right, we're gonna do a task now.

The first step is to open up the project.

The project is called Investigate Movement.

I want you to find out what each of these actions do and then record your findings.

So we have got a table here and the table columns are labelled Action and Movement, and the action column has been filled in with a lot of different events, and your job is to try them all out and write down what kind of movement happens.

Are you ready? You can go and work on that task and I'll be here when you get back.

Welcome back.

Well done for working so hard on that task.

Let's have a look at the answers.

So we have got some answers here.

This is how I recorded my movement.

When the green flag is clicked, the sprite goes back to the beginning.

When the sprite is clicked, it turns clockwise.

When the C key is pressed, it opened and closed the claws.

When the D key is pressed, the sprite turned and moved down.

When the R key is pressed, the sprite turned and moved right.

Then I found out that when the Space key is pressed, it got the sprite to follow the mouse pointer, and when the U key was pressed, the sprite turned and then moved up.

Well done for working on that problem.

Step two says, "Which commands are missing? Are there any other commands that you think would be useful to move the sprite? Share your ideas with a partner." Now, you might have tried out these movements and feel like they don't quite match what you were thinking the actions were going to trigger.

So you might have different ideas of how the sprite should move.

Share those ideas with a partner and then come back to the video.

Welcome back.

I'm sure there were lots of different ideas there, so well done for thinking about how we could change the project and find out which commands were missing.

Laura says, "I couldn't find a way to get the sprite to turn left.

Turning anti-clockwise was also missing." Thank you, Laura.

Well done for working on that part of the task.

In the next part of the lesson, we will be looking at improving sprite control.

On a project page, you press See Inside to look inside the project and see the code.

Do you see the purple button with the arrows that are pointing? It says, "See Inside." The turn block in Scratch uses degrees to set how far the sprite is turned.

All sprites start facing 90 degrees, which is facing right.

What will this code do? Have a look at the direction and the degrees in the circle.

This code will make the sprite point down and then move 10 steps.

What will this code do? Will it, A, point up, and move 10 steps? Will it, B, point left, and move 10 steps, or will it, C, point right, and move 10 steps? Pause the video here and think about your answer.

Welcome back.

Well done for working on that question.

We were looking at this code block and deciding what this code will do when it is run.

The answer was A, when the U key is pressed, the sprite will point up and then move 10 steps.

Well done if you got that one right.

For this project, you will use three categories in the menu, the motion menu, and events menu there, there, and there, and the change costume block is in the Looks menu, which is there.

The costume of a sprite changes what it looks like.

The crabs' claws are open in one costume and closed in the other costume.

In this sprite, it's not a big difference in the costume.

So look closely.

Can you see the first crab has closed claws, and the second crab has open claws? On many Scratch blocks, you can use the Dropdown menu to change the key that is used.

You can select any letter keys and some other keys too.

These are the blocks that are in this programme.

Think about what changes you could make to improve it.

So these keys are controlling the sprite moving around, changing costume, and resetting the sprite as well as turning the sprite clockwise.

Can you think of some changes you would make to improve this programme? Make sure that your choices are sensible.

Your choices should match the movement and be clear so that your code can work correctly.

Sophia says, "I want to programme the arrow keys on the keyboard for movement.

The arrows point in the direction that I want the sprites to move." Aisha says, "On my keyboard, the W and E keys are next to each other.

The letters make me think of West and East.

I will programme the turn clockwise and turn anti-clockwise actions by using these keys.

Andeep says, "I'm going to programme the costume to change when the sprite is clicked.

In my code, all of the keys will be for movement, so using the mouse click for the costume makes sense to me." All right, it's time for our task now.

I want you to choose new ways to control the sprite.

Record your plans for improvements.

So we have got another table here.

The two columns are labelled Event and Movement, and your job is to fill in the event on the left side, for example, press left arrow key.

We've put that in there for you.

And then on the right-hand side, I want you to record what the sprite will do when that event is triggered.

So in the example, the sprite will move left.

It's time for you to go off and work on your plan, and I will be here when you get back.

Welcome back.

We were working on our plans to improve the programme.

Let's see how you did.

Now this is my plan to change my programme.

Yours might look a bit different and that is fine.

So just to run down the things that I've changed or plan to change in my programme.

My second event was to press the right arrow key that would make the sprite move right.

When you press the up arrow key, the sprite moves up.

When you press the down arrow key, the sprite moves down.

When you click the sprite it changes costume.

When you press the W key, the sprite turns left, and when you press the E key, the sprite turns right.

Well done for completing this part of the task.

For the next part of the task, I want you to change the project to use your new controls.

Make sure that your sprite can do these actions.

I want you to make sure your sprite can move left, move right, move up, move down.

That is the code blocks along the top if you need them.

And then I also want you to make sure your sprite can change costume, turn clockwise, and turn anti-clockwise.

And those are the coding blocks along the bottom.

It's time to pause the video now and go and complete your projects, and I'll be here when you get back.

Well done, you have worked really hard on your projects.

This video will show you how I improved the project.

In this part of the task, I'm going to show you how to change the project to use the new controls.

So I'm going to test out these blocks and improve them.

So the first one is when D key is pressed, and when I press that, the sprite moves down.

So even though that does make sense, I'm going to change it to be even clearer.

I'm going to use the down arrow.

So now when I use the down arrow on the keyboard, the crab will move down.

The next one is the R key.

So if I tap that on my keyboard, the crab moves, right? I'm gonna update that to follow my plan.

I want it to be when I press the right arrow on my keyboard, that's great.

You can see I'm using the green flag here to reset, just like the note says.

Let's look at another one when the U key is pressed.

So let's test out the U key, sprite's moving up.

So I'm gonna change that to the up arrow.

Moving to give a bit more space there.

Now we're missing a direction.

Did you notice that? So I'm gonna need to add another event block.

I'm going to get the, When key pressed block, drag it into that space, and change it to be the left arrow.

That's correct there.

Remember, I need the point in direction and helpfully, Scratch gives you this little diagram to help you find the right direction to point your sprite.

So left is the minus 90, and then we need the move steps block.

So just make some space for it there.

Move 10 steps.

Let's test that out.

I'm gonna press the left arrow.

Yep, so now I can make my crab move in all four directions.

Excellent.

The next thing is to look at the other programmes here.

Now I was changing programmes, but sometimes it's easier to get rid of code that you don't need so that you've got space to build your own code.

So I'm gonna start with the when the sprite clicked, because in my plan when you click on the sprite, it changes costume.

So I'm gonna test that now.

There we go, my crab changing its costume when I click on it.

And then I'm going to need my turn right and turn left.

Because I haven't got them in my programme yet, I'm going to use, when key is pressed, for those as well.

I had an idea that the turn right could be E for East and the turn left could be W for West.

Let's test those out.

There we go, turn left, and turn right is also working.

I'm going to leave the green flag code because it resets my sprite.

You've worked really hard today learning all about how to move a sprite.

Let's summarise our learning.

A sprite is a graphic object that can be controlled by a programme.

Sprites can be controlled using programmed instructions.

Sprites do not move on their own, they need code to respond to inputs.

An event is an input such as a key press or a mouse click that triggers a block of commands to be run.

It is important to make clear and sensible choices such as selecting the correct keys to move a sprite in the right direction.

Thank you for joining me in this learning today, and I hope to see you again soon.