I would consider using a Raspberry PI for this since it is created for this very purpose
- CPU
- RAM
- Harddisk
- What can a computer do without an os?
- What is a filesystem?
- What is a computer program? I would use "Hello World - computer programming for kids and other beginners" and maybe scratch from mit
- Virus
- Security
- Home networking
- Servers and computers (clients)
- Privacy
- homepages
- Searching
- What makes a good security question and what doesn't.
- What is a pseudonym (eg. nickname for kids) and why do we need them to deprofile ourselves from prying eyes, instead of using our real name online.
- Why updates in general are good and should not be avoided.
- Why Facebook can be used to track people's locations and relations with other people
- It is so easy to write something on the internet in a chat or elsewhere - but there are real people in the other end of the wire and they might get hurt
No word processing and spread sheet!