What is the difference between a period and a dash?

The period and the dash are both punctuation marks used in writing to convey different meanings and purposes.

1. Period:
A period, also known as a full stop, is a punctuation mark that is used to indicate the end of a sentence. It is placed at the end of a declarative sentence, an imperative sentence, or a sentence that expresses a complete thought. The period is used to separate sentences and to create a pause, allowing the reader to take a breath and process the information before moving on to the next sentence. It is the most commonly used punctuation mark and is essential for clear and effective communication in writing.

Example: "I went to the store and bought some groceries."

2. Dash:
A dash is a punctuation mark that is longer than a hyphen and is used to create emphasis, interruption, or to indicate a sudden change in thought or tone. There are two types of dashes: the en dash (–) and the em dash (—). The en dash is slightly longer than a hyphen and is used to indicate a range or connection between two elements. The em dash is longer and is used to set off a phrase or clause within a sentence, similar to parentheses or commas, but with a stronger emphasis.

Example 1 (en dash): "The years 2010–2015 were marked by economic growth."
Example 2 (em dash): "I finally found the book I was looking for—after searching for hours."

The main difference between a period and a dash is their function and the way they are used in writing. While a period indicates the end of a sentence, a dash is used to add emphasis, create interruption, or indicate a change in thought. The period is used more frequently and is essential for grammatically correct sentences, while the dash is used sparingly for specific purposes.