You have built games and Scratch programs over the last few weeks, but where do they actually live, and what runs them? Today you will open up the machine in front of you (without a screwdriver) and trace exactly how your own game gets from storage into action.

A computer system is made of a few main parts working together:

• CPU (central processing unit): the part that carries out instructions, one after another, in order. It is the part that actually runs your game.
• Memory (RAM): fast, temporary space that holds the program and data while it is running. It empties when the power goes off.
• Main storage (the drive): slower but permanent space where your saved files and programs stay even when the machine is switched off.
• Input devices: how you put data in, such as a keyboard, mouse, touchscreen or microphone.
• Output devices: how the computer shows results, such as the screen or speakers.

Now one more idea, just two words. Hardware is the physical parts you can touch. Software is the set of instructions, the programs, that tell the hardware what to do. Your game is software; the machine running it is hardware.

Before the tour, predict: when you open your saved game, where does it travel first, and what part of the machine actually plays it? Commit to an answer with a partner.

Work with the device in front of you and one of the games or Scratch programs you saved earlier. Open your saved project. If it is missing, ask your teacher or rebuild it quickly from your plan.

1. Point to where your saved game lives when the machine is switched off. That is main storage. Write the word.
2. Open the game. It is now copied into memory so the machine can work with it quickly. Write the word and one sentence on why memory is faster but temporary.
3. Press play or the green flag. The CPU now carries out your instructions one at a time, in order, exactly as you sequenced them. Write the word.
4. Name one input device you use to control the game and one output device that shows you what is happening.
5. Finish the sentence: "My game is software because... and the laptop is hardware because..."

Now show you can recognise the parts on your own.

1. Matching. Draw a line from each component on the left to the job it does on the right. The components are: CPU; Memory (RAM); Main storage; Input device; Output device. The jobs are: carries out the program's instructions one at a time, in order; fast, temporary space holding the running program, empties when power is off; permanent space where saved files stay even when switched off; lets you put data in, such as a keyboard or touchscreen; shows results to you, such as the screen or speakers.
2. Sort. Put each of these everyday items into hardware or software: keyboard, your Scratch game, the screen, the operating system, a speaker, a web browser, the hard drive, a saved photo.
3. For any two items you found tricky, write one line saying why it goes where it does.

• Every component is matched to the correct job.
• Each item is sorted into hardware or software.
• You can explain at least two of your sorting choices in plain words.

Pull it together: your game lives in main storage, is copied into memory when opened, and the CPU then executes its instructions in order. Input devices feed it; output devices show the result. Hardware is the physical machine; software is the instructions.