Sequences: Putting Steps in Order

What is a sequence?

A sequence is steps done in order, one after another.

First you do step 1. Then step 2. Then step 3. The order never jumps around.

Computers love sequences. They do each step from top to bottom.

Steps go one at a time

Look at these steps to make a drink:

1. Get a cup.
2. Pour in the juice.
3. Take a sip!

The computer would do step 1, then step 2, then step 3. One at a time, in order.

It never does step 3 before step 1. That would be silly!

Order really matters

Let's try getting dressed:

1. Put on socks.
2. Put on shoes.

Now flip them around. Put on shoes first, then try to put on socks. Can you? No! The shoes are in the way!

This is why the order of a sequence is so important.

Sequences in code

When you write code, you make a sequence of steps. The computer follows them in order, just like a recipe.

You can see this idea in What Is an Algorithm? and try real steps in Getting Started with Scratch.

Try it yourself

Think of the steps to wash your hands:

• 💧 Turn on the water
• 🧼 Add soap
• 👏 Rub your hands
• 🚿 Rinse them clean

Now mix them up. Can you rinse before the water is on? No way! A good sequence keeps the steps in the right order.