girl.

Secondly, it is worth looking at the specific actions of each family member to glean further information. The father, for example, is mowing the lawn. The mother is bent over, picking flowers, while the two children are playing catch with a ball.

What we see, then, is a traditional, nuclear American family at leisure. The father fulfills the dominant, male role by mowing the lawn. The mother is fulfilling the traditional female role by tending to the garden to beautify the home, and the children play an innocent game in the garden. Looking deeper, the burnt silhouettes show a family tragically cut down in the prime of their lives, without any warning.

By describing this traditional family, Bradbury argues that the danger of being over-reliant on technology can affect anybody. It does not matter what kind of family you are or how you live, technology poses a real danger if it is not properly used and respected.

In "There Will Come Soft Rains," the silhouette on the wall is the most haunting image Ray Bradbury presents because it shows the instant a nuclear blast killed the unsuspecting family. Each member of the family was in the middle of some activity: the father was mowing the lawn ("the silhouette in paint of a man mowing a lawn," the mother was gardening ("Here, as in a photograph, a woman bent to pick flowers."), and a boy and girl were playing catch with a ball ("a small boy, hands flung into the air; higher up, the image of a thrown ball, and opposite him a girl, hands raised to catch a ball which never came down."). 

This image helps Bradbury develop his theme that nuclear annhilation will destroy everyone. And that this annhilation can happen at any time.

This image also helps explain the absence of people in the house. It explains why the food the house makes goes uneaten and the cards go unplayed. In addition, the absence of people makes the house meaningless. 

In general, this idea of a silhouette after a nuclear blast comes from reports of nuclear shadows on walls after the United States dropped atomic bombs on Hiroshima and Nagasaki.

"There Will Come Soft Rains" by Ray Bradbury is a story about a house in the aftermath of a nuclear bomb or disaster of some kind.  I will spare you all of the technical details about an atomic explosion.  Here is the simplified version.  It releases a ridiculous amount of energy.  A portion of that energy is light and heat.  A lot of light and heat.  So much in fact, that it is capable of vaporizing a human body.  That's what happened in the story.  The blast wave incinerated the people and left scorch marks on the building.  Because the humans were blocking the building wall with their bodies, the building did not get scorched in those locations.  So what is left on the wall is a ghostly silhouette of the humans that blocked that part of the building from being scorched.