Radio waves are absorbed by different materials depending on the material’s composition, thickness, and the frequency of the waves.
- Conductors like metals absorb radio waves effectively. When radio waves hit a metal surface, the energy is absorbed by the free electrons, which move and convert the wave energy into heat or reflect it.
- Insulators like wood, plastic, or glass usually allow radio waves to pass through, but some absorption still occurs, especially if the material is thick or contains moisture.
- Water and moist materials absorb radio waves strongly, especially at higher frequencies. That’s why radio signals weaken when passing through rain or the human body.
- Concrete and bricks partially absorb and partially reflect radio waves. Thick walls can significantly weaken or block signals.
- Frequency matters — higher-frequency radio waves (like microwaves) are absorbed more easily by many materials, while lower-frequency waves can penetrate further before being absorbed.
In summary, the absorption of radio waves depends on the type of material, its properties, and the wave’s frequency.