If you place your ear close to an iron railing which is tapped some distance away, you hear the sound twice. Explain why?

Explanation

### Step-by-Step Solution:

1. **Understanding the Setup**: When you place your ear close to an iron railing that is tapped some distance away, you are in a position to hear the sound produced by the tap.

2. **Speed of Sound in Different Media**: Sound travels at different speeds depending on the medium. In solids, like iron, sound travels faster than in gases, like air. This is due to the rigidity of the medium; the more rigid the medium, the faster the sound travels.

3. **Sound Transmission through Iron**: When the iron railing is tapped, the sound waves travel through the iron first. Since iron is a rigid medium, the sound waves travel quickly, allowing you to hear the sound almost immediately.

...