1. Definition: Electromagnetic radiation is energy that travels and spreads out as waves through space.

2. Wave Types: It includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

3. Speed: All electromagnetic waves travel at the speed of light in a vacuum, which is about 300,000 km/s.

4. No Medium Needed: It can travel through empty space—unlike sound, it doesn't need air or water to move.

5. Wavelength and Frequency: Waves have wavelengths (distance between peaks) and frequencies (how many waves per second).

6. Energy: Shorter wavelengths (like X-rays) carry more energy than longer ones (like radio waves).

7. Sources: The Sun is the main source of natural electromagnetic radiation.

8. Uses: It's used in communication, medicine, cooking (microwaves), and remote sensing.

9. Visible Light: The only part of electromagnetic radiation humans can see is called visible light.

10. Danger: High-energy radiation (like UV, X-rays, gamma rays) can be harmful to living cells.