Welcome, everyone! Today we're going to talk about a fundamental skill that's not just important for computers, but for our everyday lives as well: sequencing. Sequencing is simply the art of putting things in the correct order. Think about a recipe: if you add the flour after you bake the cake, it won't turn out right. The order of the steps is what makes the recipe work.

Computers are the same way. They can't guess or improvise. They need a set of clear instructions, and those instructions must be in the perfect sequence to get a job done. If the sequence is wrong, the program won't work. By learning to think about the correct order of things, we're developing a key skill that all programmers use every single day.

Explain to the students that you're going to play a game to practice following instructions exactly. The game is called Simon Says.

Remind them of the key rule: you should only follow a command if it starts with the phrase, "Simon says." All other commands should be ignored. You can decide if you want to play this as a knockout game or just for fun.

Play a few rounds, starting with simple commands to get everyone warmed up.

• "Simon says, touch your nose."

• "Simon says, jump."

• "Spin in a circle." (See who gets "out" here!)

• "Simon says, stand on one foot."

Observe how well students listen and ensure they understand the importance of following instructions carefully. This is a crucial skill for computer science! 

Play more rounds with your class to ensure understanding (check the teacher notes for more commands).

Tell students you’re now going to think about what happens first and what happens then. Explain that first is the thing at the start, and then is what happens right after. This is a core idea in all of coding.

Read these examples out loud to the class to get them thinking:

• "First, I wake up. Then, I get out of bed."

• "First, I put on my socks. Then, I put on my shoes."

• "First, I wash my hands. Then, I eat my lunch."

Now, ask the students to share their own examples. You can help them by prompting them with routines from your school day, like getting ready for lunch or packing up to go home.

Once they've shared, tell them that you’re going to read a story about a girl's daily routine that shows how first and then work in her day. This is a great way to show them how a sequence of events happens in the real world.

Tell the class you are going to read them a short story about a girl called Aoife, and that their job is to listen out for every first and every then.

Read the story aloud, pausing at the end of each line so the class hears the pair:

• First, Aoife's alarm clock rings. Then, she opens her eyes.

• First, she climbs out of bed. Then, she pulls back the curtains.

• First, she eats her breakfast. Then, she brushes her teeth.

• First, she packs her school bag. Then, she puts on her coat.

• First, she walks to school. Then, she hangs her coat on her peg.

• First, she sits down at her desk. Then, the school day begins.

Now read the story a second time, but stop just before each then and let the class call out what comes next. They have heard it once, so most will remember, and saying it together out loud is what makes the pattern stick.

Finish with two questions for the class to talk about:

• What if Aoife put her coat on first and packed her bag then? Would her morning still work?

• What if she brushed her teeth first and ate her breakfast then?

Draw out the point: some pairs can swap around and the day still works, but others cannot. A computer has exactly the same problem, which is why the order we give it matters so much.

Now let's put that into practice on the board. The game below shows three pictures from getting dressed, all mixed up. The class's job is to put them in the right order: what happens first, what happens then, and what comes last.

Ask a pupil to come up and drag the pictures, one at a time, into the box on the right, starting with the one that happens first. When all three are in, Digi, the character at the top of the game, will say whether the order is right.

Before each drag, ask the class: "What has to happen first? And what comes next?" If the order is wrong, press Reset and let another pupil try. Once it is right, ask why the laces cannot be tied before the shoes go on.