Logos is concerned with the logical and rational presentation of facts, whereas pathos is concerned with emotive concepts and pictures that convince. Logos can be used to persuade through arguments, while pathos uses emotion to persuade. Logos is used when trying to convince others by using facts and data, such as in essays or speeches. Pathos is used when trying to appeal to another's emotions, such as with a movie trailer or social media post. Logos is useful for scientific papers, while pathos is useful for newspaper articles or blog posts. In conclusion, logos is used when trying to convince others by using facts and data, such as in essays or speeches.