What are slow and fast changes? Give examples.

Hint: As name suggests, slow changes take more time and fast changes are rapid in terms of time. The changes that take hours or more can be classified into slow changes and that take a few seconds or minutes can be classified as fast.

Complete Step-by-Step Solution:
The changes that take a long duration of time to complete, are called slow changes. This duration can be in hours, days or even months. The changes that are completed in short or very short duration of time are called fast changes.

Examples of slow changes:
 Rusting of iron, as it takes many days.
$$F{e_{(s)}} + {O_2} \to F{e_2}{O_{3(s)}}$$
- Ripening of fruits
- Curdling of milk
- Fermentation of sugar

Examples of fast changes:
- Explosion of bomb
- Precipitation of AgCl from solution of $$AgN{O_3}$$
- Neutralization of strong acid and base

Additional Information:
There are not exact boundaries of time to define slow and fast changes but however, relatively they can be separated.
i) Slow changes involve the reactions that have very low reaction velocities. Sometimes availability of proper reagents also makes natural changes slow.
ii) While Fast changes involve reactions that have a high reaction rate. Some of the fast changes are spontaneous, meaning that they occur in a second or even less amount of time.

Note: Try to give changes as examples that involve some chemical reaction. Make sure that you define both slow and fast changes clearly. Prefer not to write an example that you are not sure whether it is a slow or fast change.