Heaney uses understatement, a dry, neutral tone, and imagery to convey sadness in this poem.

Often, emotion is most effectively communicated when a writer describes a scene using images, description employing the five senses of sight, sound, taste, touch, and smell. This is counter-intuitive, but a deadpan style that relies on description is what allows readers to experience feelings for themselves. If Heaney's speaker were to emote loudly saying "I am so devastated!! Oh my God, what a horrible tragedy!" he runs the risk of sucking all the oxygen out of the room and experiencing our emotions for us, leaving us with nothing.

Heaney very effectively does the opposite. He opens with a simple statement that describes where he was when he first heard of the accident:

I sat all morning in the college sick bay.

The second line starts to convey an ominous sense that something is not right. The speaker uses the image of a bell knelling as a literary device to foreshadow that a death has occurred: the image of a knelling or clanging bell is an allusion to the way in former times a bell would be rung to announce a death. (We might think of Donne's phrase, "Ask not for whom the bell tolls.") The third and final sentence in the first stanza returns to the deadpan, unemotional journalistic style of the first sentence, merely reporting when and how the numbed speaker got home.

In the third and fourth stanzas, the deadpan tone of numbed grief and simple imagery conveys sadness: "my father crying," as well as the death described as a "hard blow." Consonance, a poetic technique of repeating similar sounds within two words in close proximity helps place emphasis on the long "i" sounds in "crying" and "stride, which are themselves like a cry.

In the fourth stanza, "angry tearless sighs" conveys the mother's grief as the body is delivered: the word "corpse" emphasizes the reality of the death, while the imagery of "stanched and bandaged" likens the dead body to a thing, a package being delivered rather than a person.

The imagery of the color white is a symbol of death used in the sixth stanza: snowdrops are white flowers, and we can imagine the candles at a funeral vigil being white as well. The dead boy is "paler" or whiter now too, bringing home the reality of death.

Although the dead boy has a "poppy," a metaphor for a red bruise like a poppy flower on his temple, the speaker continues to use understatement in the seventh stanza by noting that the body has "no gaudy scars."

Finally, Heaney uses the poetic technique of withholding the final punch until the last, one-line stanza, in which we find out the dead boy is only four. To slow down the impact, the speaker makes us figure out the age by ourselves:

A four-foot box, a foot for every year.

The alliterative "f" sounds also slow us down and add a tolling emphasis to the final line.