The short stories are:

The sound of thunder by Ray Bradbury, and Nethergrave by Gloria skurzynski

Compare and contrast the ways these other worlds impacted the real world for the characters.

In both "The Sound of Thunder" by Ray Bradbury and "Nethergrave" by Gloria Skurzynski, the characters are transported to other worlds that have a significant impact on their perception of reality. However, the ways in which these other worlds impact the characters and the real world differ in several key aspects.

In "The Sound of Thunder," the characters travel back in time to the prehistoric era through a time machine. The impact of this adventure becomes apparent when Eckels, one of the characters, disregards the rules and steps off the designated path, causing a ripple effect that alters the present. This interruption in the natural course of events in the past changes the future drastically, leading to a dystopian reality upon their return. The other world of the prehistoric era directly influences and impacts the real world, leading to unintended consequences and chaos in the characters' timeline.

On the other hand, in "Nethergrave," the characters enter a virtual reality game called the Nethergrave, where they can escape their real-world problems and live in a fantasy world. Jeremy, the protagonist, chooses to immerse himself in this virtual world due to his loneliness and dissatisfaction with reality. Although the Nethergrave provides an alternate reality, it does not directly impact the real world. Jeremy's involvement in the game affects his personal life as he neglects his schoolwork and relationships, but it not a world that interacts with reality beyond its influence on his behavior.

In terms of similarities, both stories explore the consequences and dangers of visiting or escaping to an otherworldly realm. In "The Sound of Thunder," the disruption caused by Eckels leads to a future where society is in chaos. Similarly, in "Nethergrave," Jeremy's immersion in the virtual world isolates him from reality, putting his real-world relationships at risk. In both cases, the characters' actions in the other world ultimately impact their perception of reality and their understanding of the consequences that come with venturing into unknown territories.

Overall, while both "The Sound of Thunder" and "Nethergrave" involve characters experiencing other worlds, their impacts on the real world differ significantly. In "The Sound of Thunder," the other world directly alters the characters' reality and creates a dystopian future when disrupted. In contrast, in "Nethergrave," the virtual world impacts the protagonist's perception and behavior but does not have direct consequences beyond his personal life. These differences highlight the varied ways in which other worlds can influence and shape the characters' realities.