Margot is different from the other children because of her looks, her personality, and her experiences. Margot is "frail," and she is fair-haired and white-skinned, so much so that she looks colorless, like a washed-out photograph. Margot is quiet and withdrawn--she doesn't have the boisterous personality that many of the other children have. Her voice is soft, and often she doesn't speak at all. She keeps her distance from the other children rather than joining in their antics. In fact, she is a very sensitive girl who seems to have some deep-seated emotional issues. When she screamed when the water touched her in the showers, that confirmed to the others how odd she was. Because she can remember living on Earth where the sun shone often, she finds the constant rain on Venus oppressive, and she seems to be depressed. That's why her parents plan to send her back to Earth soon. She doesn't fit in on Venus.

Despite all those differences, the one thing that seems to set the children against Margot more than any other is that she has experiences they don't share. All the other children have a homogeneous background: They have been raised on Venus and know nothing of life outside the underground complex they live in. That Margot remembers seeing the Sun and that she knows about life on Earth first-hand makes the children jealous of her, even though Margot doesn't act like a know-it-all. Beyond that, the children know that she will have a chance to go back to Earth soon, a chance that evades the others. Her past experiences and her future plans set her apart from the others.

Why the other children dislike Margot is a strong theme in the story. Bradbury creates a scenario that allows modern Earth-bound readers to examine their prejudices. Margot represents the "other," and human beings instinctively despise those outside their own tribe. Perhaps her rich and varied experiences caused them to wish they could escape their underground home, so they became jealous. The fact that she wouldn't join their games might feel like an insult to them, so they lashed back to give her pain. But part of their dislike stems from a simple lust for power: Margot is weak and alone; they are strong and have numbers on their side. Such a condition spurs bullying, and that's what happens in the story.

Although the story is overtly about children on a different planet in the future, it makes all readers, children and adults, think about how they treat others and whether they allow prejudices to mar their behavior.

Why doesn’t Margot interact with the other children? What causes the conflict between Margot and the other children?

Bradbury doesn't explicitly tell his readers why Margot doesn't interact with the children.  The reader has to make a judgment call on the issue.  I think she doesn't interact with the other children because she is newer to Venus and the school than all of the other children.  She isn't that terribly new to the school though.  The text says that Margot arrived on Venus five years earlier.  

And then, of course, the biggest crime of all was that she had come here only five years ago from Earth, and she remembered the sun and the way the sun was and the sky was when she was four in Ohio. And they, they had been on Venus all their lives, and they had been only two years old when last the sun came out and had long since forgotten the color and heat of it and the way it really was.

That should be enough time for her to make friends and find her niche, but she never does.  I think a part of her being an outsider is partially her fault.  Sure, she is an outsider when she first comes, but I think Margot perpetuates her "differentness" by not attempting to participate in the games with the other children. 

And this was because she would play no games with them in the echoing tunnels of the underground city. If they tagged her and ran, she stood blinking after them and did not follow. When the class sang songs about happiness and life and games her lips barely moved.

I don't know why Margot doesn't interact with the other children.  The text never says, but the text seems to indicate the Margot is in a perpetual state of depression.  Scientifically speaking, that could be because of Seasonal Affective Disorder.  It's a depressed mood driven by lack of sunlight.  That sounds weird, but it's a legitimate disorder.  Margot simply might not be able to muster up the energy to appropriately interact with the other children if she is suffering from severe depression. 

The main conflict between Margot and the other children is that Margot definitely remembers what sunlight looks and feels like.  The other children do not.  That singular fact drives a wedge between Margot and the other children.  Some of the children do not believe her, and I think some of the children are flat out jealous of Margot and her memory of the sun.  

And they, they had been on Venus all their lives, and they had been only two years old when last the sun came out and had long since forgotten the color and heat of it and the way it really was.

But Margot remembered.

"It’s like a penny," she said once, eyes closed.

"No it’s not!" the children cried.

"It’s like a fire," she said, "in the stove."

"You’re lying, you don’t remember !" cried the children

What makes Margot different from the other children and why? Why does this difference cause the other children to dislike Margot?

Margot and the other children live and go to school together on Venus. Their parents are part of some undisclosed program that is working to create a civilization on Venus. On Venus, it rains continuously day and night for years on end. However, once every seven years, the sun shines for two hours.

Compared to the other children, Margot has been on Venus a relatively short time. Previously she lived on Earth and remembers it well. Supposedly on Earth, the sun still normally shines. Margot has seen and experienced the sun. The other children were born on Venus and the last time they saw the sun, they were only two years old so they do not remember it. To them, the sun is a myth and many are unsure it even really exists.

When the other children hear Margot describe the sun and say that she has seen it, they do not believe her. Margot already seemed to be an outcast, different and withdrawn from the others. Once she speaks of knowing the sun, the children actively shun her, eventually pushing and shoving her. Her descriptions are vivid and the author leaves the reader to assume that as Margot speaks, the children start to believe her and to resent her.

What is Margot's point of view, and how is it different from the other children?

It was always inevitable that Margot would have a different point of view to the other children in her class. As a relative newcomer to Venus she still harbors memories of what life was like back on planet Earth. In particular, she remembers the sun, of which the other children in her class are so desperate to catch a glimpse.

More than anything else, it's this direct experience of seeing the sun that separates Margot from her classmates. It's also what causes the other children to feel resentment and jealousy towards her. As an earthling Margot is already an outsider on Venus, and her descriptions of the sun and all its majestic beauty merely add to her outsider status.

The other children have never seen the sun before and so it's understandable that they should find Margot's descriptions of it somewhat fantastical. Although they claim that Margot's making it all up, deep down they probably know that she's telling the truth about what she saw back on earth. The truth of the matter is that they're just insanely jealous because she's seen the sun and they haven't.

It's notable in this regard that the other children's perspective changes when they finally get a chance to experience the sun for themselves. It is only then that they realize that Margot was telling the truth all along.