We hear a thunder because

Options

A. A lot of charge goes in lightning
B. The air heats up and expands all of a sudden
C. Clouds bang against each other
D. Cloud burst

Explanation

### Step-by-Step Solution:

1. **Understanding Thunder**: Thunder is the sound produced during a thunderstorm, typically associated with lightning. It is important to understand the relationship between lightning and the sound we hear.

2. **Lightning and Air**: When lightning strikes, it generates an immense amount of energy and heat. The temperature of the lightning can reach up to 30,000 Kelvin, which is several times hotter than the surface of the sun.

3. **Heating of Air**: The intense heat from the lightning causes the surrounding air to heat up rapidly. When air is heated, it expands. This rapid expansion occurs almost instantaneously.

4. **Creation of Vacuum**: As the lightning travels, it creates a path through the air. The extreme heat causes the air in that path to expand and can even lead to a temporary vacuum, as the air molecules are pushed away from the lightning bolt.

5. **Collision of Air Molecules**: Once the air expands, it creates a pressure difference. The surrounding cooler air rushes in to fill the vacuum created by the lightning. This rapid movement of air molecules collides with each other, producing sound waves.

6. **Sound of Thunder**: The sound waves generated by the collision of the rapidly moving air molecules is what we hear as thunder. The sudden expansion and subsequent collision of air molecules create the loud sound characteristic of thunder.

7. **Conclusion**: Therefore, we hear thunder because the air heats up and expands suddenly due to the energy released by the lightning strike.