The poem "We are Seven" is about an eight year old girl who is playing among the tombstones in a graveyard, and the poet observes how happily she plays and with how much energy she is invested in her playtime. When he asks her how many siblings she has, the girl insists in that there are five alive and two are in the churchyard (buried). However, she insists in that they are still seven total. This is indicative that the little girl's innocence prevents her from differentiating the pain of death from the joys of life: She is joyful regardless because she represents the innocent aspect of childhood and joy.
Wordsworth does, however, use a bit of eeriness in the beginning, because the poem begins with a sudden application of contrast in the play on words
A Simple Child,
That lightly draws its breath,
And feels its life in every limb,
What should it know of death?
Wordsworth began his stanza using childhood in the first verse, and death on the last verse, making the stanza contradictory and contrasting in that childhood and death should not go together in one same thought, and thus provoking a sense of eeriness. This is indeed an effective technique because the contrasting quality of both terms bring the reader to suspect that something will occur in the poem that will equally result in irony and even sadness.