Here are some computer science notes for class 7 based on NCERT textbooks:

1. Introduction to Computers:
- Computers are electronic devices that can perform a variety of tasks.
- They consist of hardware (physical components) and software (programs that run on the hardware).
- Computers can process data, store information, and communicate with other computers.

2. Input and Output Devices:
- Input devices are used to enter data into the computer, such as keyboard, mouse, scanner, etc.
- Output devices are used to display or print data, such as monitor, printer, speakers, etc.

3. Operating Systems:
- An operating system is a software that manages the hardware and software resources of a computer.
- Examples of operating systems are Windows, Mac OS, Linux, Android, etc.

4. Programming Languages:
- Programming languages are used to write programs that run on the computer.
- Examples of programming languages are Python, Java, C++, etc.
- Programs are written using syntax (rules for writing code) and are compiled or interpreted to run on the computer.

5. Internet and Email:
- The internet is a global network of computers that allows communication and access to information.
- Email is a way to send and receive messages over the internet.
- We use web browsers (such as Google Chrome, Mozilla Firefox, etc.) to access websites on the internet.

6. Cyber Safety and Security:
- It is important to be safe and secure online by protecting personal information and avoiding scams.
- We should use strong passwords, avoid clicking on suspicious links or emails, and use antivirus software to protect against viruses and malware.

These are some basic computer science notes for class 7 based on NCERT textbooks. It is important to study the textbooks thoroughly and practice programming to gain a better understanding of computer science concepts.